Title of Invention	AN AQUEOUS TOPICALLY APPLIED MICELLAR FORMULATION FOR CONTROLLING INTERNAL PARASITES
Abstract	Aqueous micellar formulations for topical administration of benimidazoles or salicylanilides with macrocyclic lactones to livestock for the control of endoand ecto-parasites, comprising a first active agent selected from water insoluble benzimidazoies, salicylanilides and active derivatives or salts thereof, in combination with a second active agent selected from macrocyclic lactones or active derivatives or salts thereof, and also comprising, per litre of formulation: from about 100 to about 400g veterinary acceptable surfactant(s); from about 200 to about 750g veterinary acceptable water-miscible solvent's.); and from about 50 ro about 350g water, as well as methods for dosina livestock with such formulations, and methods for controlling and/or preventing diseases or parasite infection in livestock.

Title of Invention

AN AQUEOUS TOPICALLY APPLIED MICELLAR FORMULATION FOR CONTROLLING INTERNAL PARASITES

Abstract

Aqueous micellar formulations for topical administration of benimidazoles or salicylanilides with macrocyclic lactones to livestock for the control of endoand ecto-parasites, comprising a first active agent selected from water insoluble benzimidazoies, salicylanilides and active derivatives or salts thereof, in combination with a second active agent selected from macrocyclic lactones or active derivatives or salts thereof, and also comprising, per litre of formulation: from about 100 to about 400g veterinary acceptable surfactant(s); from about 200 to about 750g veterinary acceptable water-miscible solvent's.); and from about 50 ro about 350g water, as well as methods for dosina livestock with such formulations, and methods for controlling and/or preventing diseases or parasite infection in livestock.

Full Text	Topical Parasiticide Formulations And Methods Of Treatment Technical Field This invention relates to formulations for administration of benzimidazoles or salicylanilides with macrocydic lactones to livestock for the control of endo-and/or ecto-parasites, methods for dosing livestock with such formulations, and methods for controlling and/or preventing diseases or parasite infection in livestock. Background Art A number of formulations containing active components, such as therapeutic, prophylactic and/or bioactive substances, for the treatment and/or prophylaxis of diseases or parasite infection in livestock, are known. Such formulations include tablets and solutions for oral administration, injectable solutions, treated collars and ear-tags, and topical means, including pour-on and spot-on formulations. Many of the early such formulations were intended for topical treatment/prophylaxis of ectoparasite-related conditions, designed to spread the active component over the skin and/or hair surfaces of the animal, not to administer the active component(s) to the bloodstream of the animal being treated. More recently, endoparasiticide pour-on formulations for delivery of particular active agents, including macrocydic lactones, to the bloodstream of domestic animals, such as sheep and cattle, have been developed, and these have the advantage over other administration forms, such as oral drenches and injection, of being easily applied to animals in a relatively-accurate amount. Known pour-on and spot-on formulations for endoparasiticide treatment generally utilise a non-aqueous delivery system for administering active components to animals, since the active ingredients of interest were substantially water-insoluble (particularly macrocydic lactones, levamisole base, benzimidazoles), and it was believed that dissolution of the parasiticide was necessary in order for the parasiticide to become systemically absorbed. Commercial ectoparasiticide products are available as both solvent-based and aqueous-based formulations. Water-insoluble actives have been formulated as aqueous suspension pour-on formulations, e.g., deltamethrin (a synthetic pyrethroid) for the treatment of lice on sheep (Clout S®, Schering-Plough) and cattle (Coopers® Easy Dose, Schering-Plough), and diflubenzuron (insect growth regulator, or IGR) for lice on sheep (Magnum IGR®, Schering-Plough). These treatments are characterised by low levels of actives found in tissues following treatment, reflecting little penetration of active through the skin layer. Solvent-based formulations containing the water-insoluble IGR, triflumuron (e.g., Zapp®, Bayer) for lice control on sheep are also available. At an equivalent dose rate to the aqueous-based formulations, these solvent-based formulations lead to higher tissue residues immediately after treatment. This supports the assertion that a water-insoluble active will be more easily systemically absorbed if it is solubilized in the formulation. By 'water-insoluble1, it is meant that the water solubility is insufficient for an effective amount of an endoparasiticide to be dissolved in a commercially-viable dose of a water-based pour-on formulation. Practically, a dose of pour-on formulation should not be much more than t.0mL/10kg bodyweight (for ease-of application and to prevent runoff). At this rate, a 500kg beast would receive a 50mL dose, therefore, a 2.0mL/10kg dose is not practical, as many animals weigh much more than 500 kg. Benzimidazoles and macrocyclic lactones are important classes of agents for the treatment or prevention of a number of important endoparasites of livestock, including acute or chronic liver fluke disease, best recognized in sheep and cattle, caused by the liver parasite Fasciola hepatica, and nematodes such as the Cooperia. Ostertagia, and Trichostrongylus species. Triclabendazole is a particularly effective benzimidazole, and is the most effective drug currently available against all stages of Fasciola hepatica, destroying the early immature and immature fluke migrating through the liver, as well as the adult fluke in the bile duct. Salicylanilide compounds form another important class of agents for control of endoparasites, particularly Fasciola hepatica, and nematodes, such as Haemonchus species. The salicylanilide oxyclozanide is effective against adult liver fluke (Fasciola hepatica) and immature paramphistones migrating in the intestine of cattle and the young flukes in the rumen and reticulum. Oxyclozanide is highly insoluble in water and is administered to animals in an aqueous suspension formulation by oral dosing. Commercial endectocide pour-on products containing the avermectins, ivermectin (Paramax®, Schering-Plough, Ivomec® Cattle Pour-On, Merial), moxidectin (Cydectin®,. Fort Dodge) and doramectin (Dectomax®, Pfizer), are currently available for treatment of cattle for the control or prophylaxis of a number of endo- and ectoparasites, such as lice, flies and ticks. These formulations, however, require significantly higher administration rates of the active component, as compared to oral drenching techniques, typically at least two times the oral drenching rates, in order to achieve effective biocd concentrations of the active ingredient in the animal, and to achieve the same efficacy of treatment. For example, Ivermectin oral solution ;or cattle (!vorneci?) Oral Solution for Cattle, Merial, registered in New Zealand) has a dose rate of 200 micrograms ivermectin/kg bodyweight, whereas ivomec® Cattle Pour-On has a dose rate of 500 micrograms ivermectin /kg bGdyweight. Treatment of liver fluke in cattle with anthelmintics, such as triciabendazole is generally carried out by oral drenching with a commercial product, for example Fasinex® 120 (120 g/L triclabendazoie, Novartis), as well as by injection (ivomec® Plus Antiparasitic Injection for cattle, Merial, which also controls adult liver fluke). Pour-on or spot-on formulations of salicylanilide derivatives are not currently available, usually being administered to livestock by oral drench. It would be highly desirable, in order to provide broad-scectrurr: protection against endoparasites and ectoparasites, through efficient deliver/ of water-insoluble compounds, such as benzimidazoles or saiicyianiliGes, in combination with macrocyclic iactones to the bloodstream of animals by a single, convenient topical application, rather than by oral administration. By "efficient delivery", it is meant that the active agent is administered at a rate approximating oral dosage rates, up to about twice normal oral dosage rates, to give effective blood concentrations and equivalent efficacy-International Publication No. WO00/61068 (PCT/N200/00053) discloses triciabendazole, optionally in combination with a macrocyclic Sactone, dissolved in at least one solvent, preferably administered as a pour-on formulation for control of liver fluke. Efficacy data supplied (based on a !ow natural infection fluke challenge, mean of 20), however, shows that the formulation was applied at 2.5 times the dose of a standard oral drench rate to give equivalent efficacy. Also, two of the solvents described, xylene and toluene, are highly flammable. The reported triciabendazole content of the formulation, after 345 days storage at ambient temperature, is 7.5% lower than the initial assay, although there is no decrease in the abamectin content. Solvent-based formulations of ivermectin can break down rapidly unless suitably stabilized. A solvent-based, topically-administered formulation of the salicylanilide closantel with the macrocyclic lactone ivermectin, for the control of parasites, has been described in U.S. Patent No. 6,340,672. The maximum concentration of active agents described in the examples of this document is 0.5%w/v for ivermectin and 5%w/v for closantel. At these concentrations, unacceptably large volumes of the formulations (from a practical viewpoint) would need to be poured onto the animals in order to achieve effective blood concentrations of the active agents. WO 00/74489 (PCT/NZOO/00087) discloses biocidal compositions, including pour-on formulations which are water-in-oil (soyabean) emulsions stabilized with an emulsifying agent. The formulations comprise the water-soluble anthelmintic, levamisole (as the hydrochloride salt), and a macrocyclic lactone (abamectin or ivermectin), optionally in combination with a benzimidazole (oxfendazole). Only low levels of benzimidazole are present in the formulations disclosed in this document (up to 5%w/v oxfendazole in an oral drench formulation), and only one pour-on formulation comprising a benzimidazole (2-.26%w/v oxfendazole) and a macrocyclic lactone (0.1%w/v abamectin) is disclosed. Whilst this pour-on formulation is described as delivering the levamisole to the bloodstream of cattle with efficiency similar to oral drench administration, the macrocyclic lactones and benzimidazoles were delivered with low efficiency and a commercially-unpractical volume of this formulation would be required to be applied to animals in order to achieve effective blood concentrations of these actives. Objects of the Invention It is an object of this invention to provide a topical formulation capable of efficient delivery of a benzimidazole or salicylanilide, in combination with a macrocyclic lactone, to the bloodstream of an animal for broad-spectrum control of endoparasites, such as liver fluke and nematodes, in animals, such as sheep and cattle, with-a-single, easily-applied topicalformulation. Summary of the Invention It has now been surprisingly found that a benzimidazole or a salicylanilide, in combination with a macrocyclic lactone, may be formulated into a stable aqueous micellar composition which, when applied topically to an animal, efficiently delivers the desired active constituents to the bloodstream of the animal, and provides effective protection against infestation by endoparasites such as liver fluke and nematodes. Thus, the present invention provides an aqueous mlcaiiar formulation comprising a first active agent selected from benzimidazoles, salicylanilides and active derivatives or salts thereof, in combination with a second active agent selected from macrocyclic lactones or active derivatives or salts thereof, saia formulation being for topical application to animals for the control of internal parasites anc also comprising, per litre of formulation; from about 100g to about 400g veterinary-acceptable surfactant(s); from about 200g to about 750g veterinary-acceptable water-rniscible solvent(s); and from about 50g to about 350g water. Surprisingly, it has also been found that the stability of aqueous miceilar formulations of the invention may be improved by inclusion of a stabilizer selected from anionic surfactants, such as sodium dodecyl sulphate (SDS), and/or buffering agents, such as soluble phosphates and/or dibasic phosphates. Thus, in a preferred aspect of the invention, the aqueous micellar formulation comprises a stabilizer selected from anionic surfactants or buffering agents, or mixtures thereof. Preferably the stabilizer is a linear alky! sulphate, such as sodium dodecyl sulphate, or one or more phosphates/dibasic phosphates, or mixtures thereof. In a preferred embodiment, there is provided an aqueous micellar formulation comprising a benzimidazole in combination with a macrocyclic lactone, said formulation being for topical application to animals for the control of internal parasites and also comprising, per litre of formulation: about 100g to about 300g poiyoxyalkyler.e sorbitan fatty acid ester surfactant; about 300g to about 650g alkylene glycol ether selected from alkylene or dialkylene glycol monoalkyi ethers or combinations thereof; about 10g to about 100g polyethylene glycci; about 5g to about 50g stabilizer; and about 50g to about 350g water. in a particularly preferred aspect of this embodiment, the formulation comprises, per litre formulation: about 180g to about 240g benzimidazole; about 7.5g to about 20g macrocyciic lactone or an active derivative or salt thereof; about 150g to about 250g polyoxyethyiene (20) sorbitan monoiaurate; about 450g to about 550g diethylene glycol monobutyl ether; about 20g to about 50g PEG 200; about 20g sodium dodecyi sulphate; and about 100g to about 200g water. The invention also provides a,method of treating or preventing a diseased or parasite-infested state in a mammal, comprising topically administering to said mammal a micellar formulation according to the instant invention. Typically, the diseased or infested state is related to liver fluke, such as caused by Fasciola hepatica, and nematodes, such as Cooperia, Ostertagia, Trichostrongylus and Haemonchus species, or combinations thereof. Even more typically, the diseased or infested state to be treated or prevented is a disease or infested state of cattle or sheep, more typically cattle. Surprisingly, it was found that the location and size of the region of topical administration of the formulations was important for efficiency of permeation of the active agents across the skin into the bloodstream. Thus, in a preferred aspect of the methods of treatment, the formulation is applied in a band along the lower portion of the back of the mammal. Preferably, so as to maximise efficiency of delivery of the active agents to the bloodstream of the animal, the formulation is applied to the animal over as small a region as possible while avoiding run-off of the formulation/so as to maximise the concentration of active agents per cm2 of animal surface. In another preferred aspect of the methods of treatment, the formulation is sprayed onto the back of the animal. Where the animals to be treated are cattle, the formulation is preferably applied to the flat part of the back, typically the last third of the animal, and most typically starting from the thoracic vertebrae and proceeding towards the rump of the animal. Typically, about 24mg benzimidazole/salicylanilide and about 1.5mg macrocyclic lactone are applied per kilogram of animal. Typically, the band of formulation applied will be from about 5cm to about 15cm wide and, depending on the size of animal, about 20cm -to 40cm long, and even more typically, the formulation is sprayed onto the back of the animal and the height of the source of spray relative to the back of the animal is maintained at about 5cm to 10cm. As used herein, the term "treating or preventing", refers to any and all uses which remedy or prevent a diseased or infested state or symptoms, or otherwise prevent, hinder, retard, or reverse the progression of disease/infestation or other undesirable symptoms in any way whatsoever. 'Infestation11 and corresponding derived terms relate to infestation by endo- and/or ecto-parasites. An "effective amount", as referred to herein, includes a non-toxic therapeutic or prophylactic amount of an active agent adequate to provide the desired effect. The "effective amount" will vary from subject-to-subject, depending on one or more of a number of factors amongst, for example, the particular agent being administered, the type and/or severity of a condition being treated, the species being treated, the weight, age and general condition of the subject and the mode of administration. For any given case, an appropriate "effective amount" may be determined by one of ordinary skill in the art using only routine experimentation. Also, extensive literature is available for many known active agents through, for example, manufacturers' catalogues, the Internet, scientific journals and patent literature, including effective amounts for administration to target animals. Typically, "effective amount" refers to an amount of active agent sufficient to result in one or more or the following: recession/reduction in the extent of a disease/infestation; inhibition of disease/infestation growth or progression; cessation of disease/infestation growth or progression; prevention of disease/infestation; relief of disease/infestation-imposed discomfort; or prolongation of life of the animal having the disease. As used herein, the term "about", in the context of concentrations of components of the formulations, typically means +/- 5% of the stated value, more typically +/-4% of the stated value, more typically +/- 3% of the stated value, more typically, +/- 2% of the stated value, even more typically +/- 1% of the stated value, and even more typically +/- 0.5% of the stated value. As ufeed herein, the term "comprising" means Including principally, but not necessarily solely". Variations of the word "comprising", such as "comprise" and "comprises", have correspondingly similar meanings. Detailed Description of the Invention Aqueous Micellar formulations The present invention is based on the finding that hydrochcbic active agents, such as benzimidazoles and salicylanilides, may be orovided in a formulation for topical administration along with therapeutic amounts of a macrocyciic iactone for efficient delivery of both the benzimidazole/salicylanilide and the macrocyciic Iactone to the bloodstream of the animal for effective control of encoparasites such as liver fluke and nematodes. It has also been found by the present investigations that efficiency of delivery of the active agents to the bloodstream of a mammal is affected by the topical location of application of the formulation, minimising the area of the skin to which the active agents are applied and/or use of formulations having elevated concentrations of the active agents. The formulations of the present invention surprisingly allow for elevated concentrations of benzimidazole(s) or saiicylanilide(s), in combination with one or more macrocyciic lactones, to be provided in a single composition for efficient delivery of the active agents to the bloodstream of a mammal by topical administration. The formulations are aqueous micellar compositions, comprising elevated levels of the active agents and, per litre of formulation: from about 100g to 400g veterinary-acceptable surfactant(s); from 200g to 750g veterinary-acceptable water-miscible solvents); and from 50g to 350g water. Advantageously, the surfactant is non-ionic and selected from scrbitan esters, polyoxyalkylated sorbitan esters, polyoxyalkylated alkyi ethers, polyoxyalkylated fatty alcohols, polyoxyalkylated fatty acids, polyalkyiene glycol esters, polyoxyalkylated derivatives of castor oil, polyglycerol esters, copoiymers of ethylene oxide and propylene oxide; amine ethoxylates; alkyi phenol ethoxylates; alkyi polysaccharides; or combinations thereof, although the surfactant may also be, or include, anionic surfactants seiected from linear alkylbenzene sulphonates; C12-to-C16 alcohol sulphates; C12 alkoxypolyethanoxy sulphates; alkyl phosphates and phosphonates or combinations thereof. Preferred surfactants are selected from polyoxyalkylated fatty alcohols and polyoxyethylene sorbitan- or sorbitol- fatty acid esters or combinations thereof, and particularly preferred are polyoxyethylene sorbitan- or sorbitol- fatty acid esters. Generally, the polyoxyalkylene sorbitan- or sorbitol- fatty acid esters are polyoxyethylene sorbitan fatty acid esters. Poiyoxyethylene sorbitan fatty acid esters such as those of the Ecoteric® series (Huntsman) are preferred. Especially preferred polyoxyethylene sorbitan fatty acid ester surfactants are polyoxyethylene (20) sorbitan monolaurate (Ecoteric® T 20) and polyoxyethylene (20) sorbitan monooleate (Ecoteric® T 80), Typically the polyoxylated fatty alcohols are poiyalkylene oxide derivatives of natural or synthetic alcohols, and those of synthetic alcohols, such as provided by the Teric® series (Huntsman) are preferred. Especially preferred is Teric® BL8. Generally, the amount of surfactant used in the formulation ranges from about 100g/L to about 400g/L, typically about 100g/L to about 300g/L, more typically about 150g/L to about 300g/Lf even more typically about 150g/L to about 250g surfactant, and even more typically about 175g/L to about 225g/L preferably about 200g/L, based on the total amount of formulation. The water-miscible solyent(s) may be selected from: ethanol; isopropanol; benzyl alcohol; glycol ethers; liquid polyoxyethylene glycols; or a mixture of at least two of these solvents. Particularly-preferred water-miscible solvents are the glycol ethers, and particularly in combination with a liquid polyethylene glycol. A particularly-preferred polyethylene glycol is PEG 200. Generally, the glycol ethers are alkylene glycol alkyl ethers, including ethylene glycol monoethyl ether, ethylene glycol monomethyl ether, propylene giycol monomethyl ether (Glysolv PM®, Huntsman), dipropylene glycol monomethyl ether, diethylene glycol monoethyl ether (Ethyl di Glysolv®, Huntsman), diethylene glycol monobutyl ether (Butyl di Glysoiv® or Butyl Digol®, Huntsman), and diethylene glycol diethyl ether and the like. Particularly preferred glycol ethers are diethylene glycol moncethyl ether (Ethyl di Glysoiv®) and/or dierhylene glycol monobutyl ether (Butyl di Glysoiv® or Butyl Digol®). Generally, the amount of water-miscibie solvent(s) used in the formulation ranges from about 200g/L to about 750g/L, typically about 300g/L to about 650g/L more typically about 300g/L to about 550g/L and even more typically about 400g/L to about 550g/L, preferably about 45Og/L to about 550g/L, based on the tcta! amount of formulation, but will vary depending on the particular soivent(s) used and the amount of active agents to be included in the micellar formulation. Where, according to a preferred aspect of the invention, the formulation comprises both a glycol ether and a liquid polyethylene giycoi, the amount of glycoi ether used in the formulation typically ranges from about 350g/L to about 650g/L, more typically about 400g/L to about 600g/L and even mere typically about 450g/L to about 550g/L, preferably about 450g/L to about 5QQg/L based on the total amount of formulation. The amount of liquid polyethylene glycol used in the formulation typically ranges from about lOg/L to about tOOg/l, more typically from about 20g/L to about 70g/L, even more typically from about 20g/L to about 50g/L, preferably about 30g/L, based on the total amount of formulation. Generally, the amount of water used in the formulation ranges from about 50g/L to about 350g/L, typically about 100g/L to about 300g/L more typically about 100g/L to about 250g/Lt and even more typically about 150g/L to about 200g/L, preferably about 150g/L, based on the total amount of formulation. Examples of suitable benzimidazoles include: 2-(4-thiazoIyl)-1H-benzimiclazole, known as thiabendazole; [5-(propylthio)-1H-benzimidazol-2-yl]carbamic acid methyl ester, known as albendazcie; [5-(propylsulfinyl)-1 H-benzimidazol-2-yl]carbamic acid methyl ester known as albendazole sulfoxide or albendazole oxide; [2-(4-thiazolyl)-1H-benzimidazol-5-yl]carbamic^ acid 1-methylethyl ester, known as cambendazofe; [5-(phenylthio)-1H-benzimidazol-2-y!]carbamic acid methyl ester, known as fenbendazole; (5-benzoyl-1H-benzimidazol-2-yi)carbamic acid methyl ester, known as mebendazcle; [5-(phenylsulfinyi)-1H-benzimidazoi-2-yl]carbamic acid methyl ester, known as is oxfendazole; (5-propoxy-1H-benzimidazol-2-yI)carbamic acid methyl ester, known as oxibendazole; [5-{N- butyl)-1H-benzimidazol-2-yl]carbamic acid methyl ester known as parbendazole; methyl 5-cyclopropylcarbonyl-1H-benzimidazol-2-ylcarbamate known as cyclobendazole; methyl 5-(4-fluorobenzoyl)-1H-benzimidazol-2:ylcarbamate known as fiubendazole; S-chloro-e^.S-dichlorophenoxy^-Cmethylthio)-benzimidazole known as triclabendazole; and [5-(4-fIuoro-phenylsulfonyloxy)-1H-benzimidazol-2-yl]carbamic acid methyl ester known as luxabendazole. The benzimidazole antiparasitic agents are active against one or more of Haemonchus, Ostertagia, Trichostrongylus, Nematodirus, Cooperia, Bunostomum, Strcngyloides, Trichuris, Oesophagostomum, Chabertia, Dictyocaulus, Mcniezia and Fasciola in sheep and against Haemonchus, Ostertagia, Trichostrongylus, Nematodirus, Cooperia, Bunostomum, Capillaria, Strongyloides, Trichuris, Oesophagostomum, Chabertia, Dictyocaulus, Moniezia and Fasciola in cattle. Particularly preferred as benzimidazole is triclabendazole. Examples of suitable salicylanilide compounds for use in the control of Fasciola and Haemonchus species in livestock include oxyclozanide (3,3\5,5\6- pentachlcro-2t-hydroxysalicylanilide), closantel (S'-chloro^'^-chloro-alpha- cyanobenzyl)-3,5-diiodosalicyl-o-toluidide), rafoxanide (3'-chlon>4'-(4- chlorophenoxy)-3,5-diiodosalicylanilide), and niclosamide (2\5-dichloro-4'-nitrosalicylanilide), as well as clioxanide, brotianide and bromoxanide. Salicylanilide derivatives, and their use for control of endoparasites in livestock, has been described in, for example, U.S. Patent numbers 3,914,418; 3,927,071; 3,989,826; 4,005,218; and 4,025,647, "Veterinary Anthelmintics", by J.H. Arundel, University of Sydney, Post Graduate Foundation in Veterinary Science, and the Merck Veterinary Manual (http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/191415.htm). Oxyclozanide is a particularly preferred salicylanilide for use in formulations according to the invention. Typically, the macrocyclic iactone(s) is/are selected from the group consisting of ivermectin (22,23-dihydroavermectin Bi described in EP 295117), abamectin, avermectin Aia, avermectin A1bi avermectin A2a, avermectin A2b, avermectin B-ia, avermectin Bib, avermectin B2a, and avermectin B2t>. Also typically, the 4 macrocyclic lactone may be selected from active derivatives of the naturally occurring avermectins, such as derivatives which have a group at the 25- substituent other than the isopropyl or (S)-sec-butyl groups, as set out in European patent applications 0214731, 0284176, 0308145. 0317148, C335541 and 0340832. Also, typically, the rnacrccyciic lactone of the first aspect of the invention can include moxidectin (and derivatives disclosec n European patent publication No. 259779A), doramectin and its analogues (described ;n European patent publication No. 02147318), selamectin. eprinomectin, milbemycin including milbemycin oxime, milbemycin D (Antibiotic S41D" and its analogues (described in U.S. Patent No. 3,950,360} and nemadectirs (described :r European patent publication No. 170006A). 01 i he macrocyclic lactone antiparasitlc agents are active against one or .-nore Haemonchus, Ostertagia, Trichcstrohgylus, Nema icdirus, Cooperia; Strongyloides, Trichuris, Oesophagcsiomum, Chabertia and Dicryocauius in sheep and against Haemonchus, Ostertagia, Trichostrongylus, Nematodirus. Cooperia, Oesophagostomum and Dictyocaulus in cattle. Particularly preferred as a macrocyclic lactone is ivermectin. Generally, where present, the amount of benzimidazole used in the formulation ranges from about 90g/L to about 360g/l, typically about SCg/L to about 300g/L, more typically about 150g/L to about 300g/L, even more typically about 180g/L to about 270g/L, and even more typically about 180g/L to about 240g/L, preferably about 240g/L, based on the total amount of formulation. Generally about 9mc to about 36mg, typically about 9mg to about 30mg, more typically about 15mg to about 30mg, even more typically about 18mg to about 27iTig1 and even more typically 18mg to about 24mg, preferably about 2^mg of benzimidazole per Kg bodyweight are applied topically to a mammal in a single dosage. Generally, where present, the amount of saHcylaniiide used in the formulation ranges from about 125g/L to about 50Og/L, typically abcut 160g/L to about 375g/L, more typically about 2O0g/L to about 350g/L, even -ore typically abcut 250g/L to about 350g/L, and even more typically about 300g/L to about 330g/L, preferably about 330g/L based on the total amount of formulation. Generally, about 12.5mg to about 50mg of oxyciozanide, typically about 16mg to about 37.5mg, more typically about 20mg to about 35mg, even more typicairy'about 25mg to about 35mg, and even more typically about 30mg to about 35mgt preferably about 33mg of salicylanilide per kg bodyweight is applied topically to a mammal in a single dosage. Generally the amount of macrocyclic lactone used in the formulation ranges from about 2.5g/L to about 25g/L, typically about 4g/L to about 20g/L, more typically about 7.5g/L to about 20g/L and even more typically about 7.5g/L to about 15g/L,. preferably about 15g/L, based on the total amount of formulation. Generally about 0.25mg to about 2.5mg, typically about 0.4 to about 2.Qmg, more typically about 0.75mg to about 2.0mg, even more typically about 0.75mg to about 1.5mg, preferably about 1.5mg of macrocyclic lactone per kg bcdyweight are applied topically to a mammal in a single dosage. Advantageously, the aqueous micellar formulations according to the invention also comprise a stabilizer. Preferably the stabilizer is selected from anionic surfactants such as linear alkyl sulphates (for example, sodium dodecyl sulphate), linear alkyl benzene sulphonates (such as calcium dodecyl benzene sulphonate) and buffering agents, typically selected from soluble monobasic and/or dibasic phosphates. Sodium dodecyl sulphate is typically used as a stabiiizer in the formulation in the range of from about 10g/L to about 30g/L, more typically from about lOg/L to about 20g/L, based on the total amount of formulation; phosphates are typically used in the formulation in the range of from about 1g/L to about 10g/L, more typically from about 1g/L to about 5g/L, and more typically from about 1g/L to 2g/L, based on the total amount of formulation. The aqueous micellar formulations may also include one or more further veterinary excipients, provided these do not destabilise the micellar formulation. Veterinary acceptable excipients for use in preparing the formulations may include, for example: further solvents such as, for example, water immiscible solvents including glycol ether esters; viscosity modifiers/suspending agents, for example, gelatin, vegetable gums such as xanthan gum, cellulose derivatives (e.g. microcrystalline cellulose, anionic or non-ionic csiluicse ethers, such as carboxymethylcellulose), fumed silica (colloidal silicon dioxide), or polyvinylpyrrolidone polymers, and magnesium aluminium silicates such as VEEGUM® (R.T. Vanderbilt), and mixtures of these. Examples of suitable veterinary acceptable adjuvants include dyes. Dyes enable the treated mammals to be distinguished from the untreated. The dyestuff may be dissolved, suspended or dispersed in the carrier. The nature of the colouring agent is unimportant and a wide variety of suitable dyes and pigments will be known to the skilled person. The colouring agent may be solubie or insoluble in water. Generally, however, the dyestuff will be biodegradable so as to fade and not permanently mark the skin or fleece. Some examples of suitable dye agents include: FD&C Brilliant Biue No. 1 (Brilliant Blue FCF, Hexacol Brilliant Blue), and Fast Scarlet Pigment 36 Processes for the preparation of miceJIar formulations of the invention The micellar formulations according to the invention may be prepared by methods and techniques known to those of skill in the art. Typically the formulations may be made using a simple process: Step 1. Charge 80% of the total volume of water-miscible (non flammable) solvent and the surfactant to a manufacturing vessel. Heat to 40°C - 75°C (flammable solvents such "as ethanol and isopropanol, whether added as major water-miscible solvent or as a minor component should be used at ambient temperature). Step 2. Add the benzimidazole or saiicylaniiide incrementally with continued stirring and heating until dissolved. Step 3. Add sequentially the water, and optionally stabilizers and dye, stirring until dissolved. Step 4. Cool to room temperature with continued stirring. Step 5. Add the macrocyclic lactone incrementally with stirring until dissolved (also, if flammable solvents such as ethanol or isopropanol are to be added as co-solvents, they should be added here). Step 6. Add the remaining solvent to volume. Methods of Treatment and/or prevention of diseases or infestations The formulations according to the invention may be used for the treatment and/or prevention of diseases or infestations by endoparasites in mammals, typically in livestock such as sheep or cattle, by applying the formulation(s) to the back of the mammal. Important diseases/infestations which may be controlled include liver fluke, nematodes and lice in sheep and cattle and buffalo fly and ticks on cattle. It was found that optimal uptake of the active agents into the bloodstream of treated mammals occurred when the formulations were applied to a region starting from the flat part of an animals back - approximately at the location of the thoracic vertebrae - and working towards the rump of the animal, effectively resulting in application of the formulation to the last third of the mammal's back. This mode of application was found to be significantly more effective than application starting at the neck. Efficiency of delivery of the active agents to the bloodstream of a mammal was also found to be greatest where the surface area to which the formulation is applied was minimised, while avoiding run-off of the formulation, so as to maximise the concentration of active agents per cm2 of animal surface, typically covering an area of about 100cm2 to about 400cm2 for cattle and about 100cm2 for sheep. Typically the formulation is applied by spray onto the mammal's back, preferably from a constant height relative to the mammal's back. For cattle, the band of formulation is typically applied starting from the thoracic vertebrae and proceeding towards the rump of the animal. Typically, from about 18mg to about 24mg benzimidazole and from about 0.75mg to about 2.0mg macrocyclic lactone are applied per kilogram animal. More typically, where triclabendazole and ivermectin are the active agents comprised in the formulation from about 18mg to about 24mg, preferably about 24mg triclabendazole and from about 0.75mg to about 2.0mg, preferably about 1.5mg ivermectin are applied per kilogram of animal. Preferably this amount of active agents is applied to the mammal in about 0.05mL to about 0.1 mL per kg animal, and in a band from about 5cm to about 15cm wide. In weaned calves typically weighing from about 100cm to about 180kg per head, good results were obtained by spraying about 10mL to about 18mL formulation onto the backs of the animals, starting from the thoracic vertebrae and working towards the animals' rumps, from a constant height of about 15cm relative the backs of the animals, resulting in an applied band of formulation about 10cm to about 15cm wide and about 20cm long. Preferred forms of the present invention will now be described, by way of example only, with reference to the following examples, including comparative data, and which are not to be taken to be limiting to the scope or spirit of the invention in anyway. Examples Example 1 - Aqueous micellar formulations, and processes for preparing them 1.1 Formulation A Component g/L Triclabendazole 240 Ivermectin 7.5 Polyoxyethylene (20) sorbitan monolaurate (Ecotenc5 T 20) 200 Polyethylene glycol 200 (PEG 200) 30 Water 150 Sodium dodecyl sulphate 20 Brilliant Blue FCF 0.16 Diethylene glycol monobutyl ether to 1L 1.2 Formulation B Component g/L Triclabendazole 240 Ivermectin 7.5 Polyoxyethylene (20) sorbitan monoiaurate (Ecoteric® T 20) 200 Polyethylene glycoi 200 (PEG 200) . 30" Water 250 Sodium dodecyl sulphate 20 Brilliant Blue FCF 0.15 Diethylene glycol monobutyl ether to 1L 1.3 Formulation C Component g/L Triclabenclazole 120 Ivermectin 5.0 Poiyalkylene oxide derivative of synthetic alcohol (Teric® BL8) 200 Benzyl alcohol 30 Water 150 Dihydrogen sodium phosphate 7.84 Disodium hydrogen phosphate 0.91. Brilliant Blue FCF 0.16 Diethylene glycol monobutyl ether to 1L 1.4 Formulation D Component g/L Triclabendazole . 120 Ivermectin 5.0 Polyoxyethylene (20) sorbitan monooleate (Ecoteric® T 80) 200 Benzyl alcohol 30 Water 250 Disodium hydrogen phosphate 0.91 Dihydrogen sodium phosphate 7.84 Brilliant Blue FCF 0.16 Propylene glycol monomethyl ether (Glysolv PM®) to 1L 1.5 Formulation E Component g/L Oxyclozanide 350 Ivermectin 7.5 Polyoxyethylene (20) sorbitan monooleate (Ecoteric® T 80) 200 Water 150 Sodium dodecyl sulphate 20 Brilliant Blue FCF 0.16 Diethylene glycol monobutyl ether to 1L 1.6 Formulation F Component g/L Triclabendazole 240 Ivermectin 10.0 Polyoxyethylene (20) sorbitan monolaurate (Ecoteric T 20) 200 Polyethylene glycol 200 (PEG 200) 30 Water 150 Sodium dodecyl sulphate 20 Brilliant Blue FCF 0 16 Diethylene glycol monobutyl ether to 1L 1.7 Formulation G Component g/L Triclabendazole 240 ■ Ivermectin - 15.0 Polyoxyethylene (20) sorbitan monolaurate (Ecoteric T 20} 200 Polyethylene glycol 200 (PEG 200) 30 Water 150 Sodium dodecyl sulphate 20 Brilliant Blue FCF 0.16 Diethylene giycol monobutyl ether to 1L Other stable aqueous micellar formulations according to the invention are described in Examples 2 and 3. The formulations were prepared by the following procedure: Stepi. Charge 80% of the total volume of water-miscibie solvent and the surfactant to a manufacturing vessel. Heat to 40 - 753C with stirring. Step 2. Add the benzimidazole or salicyianilide incrementally with continued stirring and heating until dissolved. Step3. Add sequentially the water, and optionally stabilizers and dye, stirring until dissolved. Step4. Cool to room temperature with continued stirring. Step 5. Add the macrocyclic lactone incrementally with stirring until dissolved. Step 6. Add the remaining solvent to volume. Example 2 - Pharmacokinetic studies Materials and methods Formulations according to the invention were tested for their efficacy in delivering benzimidazoles and macrocyclic lactones to the bloodstream of mammals (cattle), and compared to the efficacy in delivering these agents to animals' bloodstreams by standard commercially available drench (Fasinex 120®), and an experimental solvent-based triclabendazole/ ivermectin pour-on formulation. Cattle (typically Hereford or Hereford cross) with either natural or artificially infected burdens of fluke and nematodes were used in pen and field trials. Within a given trial animals were allotted into treatment groups, each having similar mean weights and fluke and nematode burdens. Experimental treatments were applied along the backl-ine using a commercially available backliner gun fitted with a plastic shroud to ensure correct delivery of the formulation according to the protocol. Blood samples (plasma) were taken by venipuncture of the jugular vein at the designated time intervals. Analysis for triclabendazole and ivermectin residues in the plasma was carried out and reported by commercial contract laboratories . Ivermectin was extracted from the plasma using acetonitrile and concentrated by svaporation. The sample was cleaned up by solid phase extraction (SPE) :hromatography and the ivermectin determined as the N-methyl imidazole jerivative using reverse phase HPLC with fluorescence detection. The triclabendazoie was extracted from the plasma using ethyl acetate. Following concentration ancr SPE clean up, the triclabendazoie and its sulphone and >uiphoxide metabolites were analysed by reverse phase HPLC using UV letection. Results Initial feasibility studies for development of an efficient fiukicide product were based on the pharmacokinetic profile of triciabendazole only. Although noting that the bioavailability of the active agents is always delayed after application as a pour-on formulation compared to a drench treatment, bleed plasma levels for the experimental formulations were targeted at the maximum triciabendazole plasma levels (Cmax) produced by the currently available fiukicide, Fasirex® 120 (triciabendazole Cmax 16.5^g/mL after 2 days) , when applied at a rate of 12mg/kg bodyweight. Having reference to Tabie 1, the following results were obtain ou In a first feasibility trial (Hereford male weaner cattle, average weight of approximately 200kg, 2 animals per group), a solvent-based formulation (N-methyl pyrrolidone/ Butyl diGlysolv®, Formulation 1), tridabendazole was aopfied at 50mg/kg to achieve similar plasma levels as per the currently available fiukicide, Fasinex® 120 (15.7jig/mL after 7 days). Such a dose rate is not commercially viable. In a second feasibility trial (Hereford male-and female weaner cattle, average weight of approximately 160kg, 3 animals per group) the triciabendazoie dose rate was reduced to a more commercially acceptable (eve! (12mg/kg). A surfactant (Teric® BL8) was added to Formulation 1 to improve the formulation's hide wettabiiity to produce Formulation 2 (non aqueous micelle), and N-methyi pyrrolidine solvent was removed. Triciabendazoie Crn3X (total metabolite) plasma levels achieved were low (2.0jag/mL). Addition of 15 % water to Formulation 1 produced Formulation 3 (Formulation C described in Example 1.3 above, an aqueous micelle), and this increased the triciabendazole Cmax achieved to 4.8jag/mL in a further feasibility trial (Hereford female cattle, average weight of approximately 235kg, 3 animals per group), the water content in the formulation was increased to 25% and Butyl di Giysolv® was replaced with Glysolv PM®. The resulting Formulation 4, provided an increased triciabendazole Cm3x of 8.7jag/mL - almost double that achieved with Formulation 3. The ivermectin Cmax achieved was 1.3ng/mL at 5 days. A similar formulation, Formulation 5, had a water content of 15 %. Although the Cmax for triciabendazole was almost the same, 8.6^g/mL, the Cmax for ivermectin was 2.6ng/mL at 2 days. Replacing Teric® BL8 in Formulation 4 with Ecoteric® T20 resulted in - -Formulation 6 (with a water content of 25%) - this formulation achieved substantially the same plasma levels as Fasinex® 120 drench (triciabendazole Cmax of 15.9fig/mL versus 16.5jig/mL) applied at the equivalent dose rate of 12mg/kg. The Cmax achieved for ivermectin was 2.8ng/mL at 5 days. Formulation 7 again showed increased bioavaiiabiiity of iriclabendazole when Teric® BL8 was replaced with Ecoteric® T30. The Cma* achieved for triclabendazoie was 12.9j.ig/mL and the C m3, achieved for ivermectin was 3.0ng/mLat2days. Having reference to Table 2, in 3 further feasibility trlai (Hereford female weaner cattle, average weight of approximately 2G0kgf 3 animals per group) reduction of the water content of the formulations to ISGg/L, and reverting to Eccteric^ T20 in place of Ecoteric® T80, increased the efficiency of delivery of ivermectin, the ivermectin plasma Cmax values for the formulations ranging from cng/mL ic 13ng/mL. From the results provided in Tables 1 and 2, it s aoparent that the pharmacokinetics of the active agents can be altered as desired by manipulating the water content, and the type and content of the surfactant and/or the co-solvent used in micellar formulations according to the invention. Manipulation of the solvent and co-solvent type has also been found during the course of these experiments to affect the physical stability of the miceilar formulations, use of a combination of Butyl diGlysolv® and PEG 200 providing the best cold storage stability and highest maximum concentration for triclabendazole of the formulations tested, thereby providing a more rugged product suitable for application tc animals in the cooler months of late autumn or early spring - although there is no published data, it has been reported thai greater amounts of active components need to be applied to animals in colder months to get the required efficacy, and these months are typically the most important in liver fluke control. Example 3 - Dosing studies Example 3.1 - Concentration affect (constant volume) Having reference to Table 2, it can be seen that altering the concentration of triclabendazole and/or ivermectin in the aqueous miceliar formulations of the invention provides a corresponding change in AUC, when applied to the animal in the same volume of formulation (1mL applied/ 10kg animal). Example 3.2 - Concentration effect (constant dose) Having reference to Table 3, in a critical slaughter efficacy trial of formulations according to the invention (methods as per Example 2; mixed sex Hereford weaner cattle, average weight of approximately 200kg, 5 animals per group), an aqueous miceilar formulation according to the invention comprising triclabendazole at 240g/l, but varying ivermectin concentration was applied at a constant ivermectin dosage rate (0.5mg/kg)f but varying triciabendazoie dosage rate(12to36mg/kg). The results show that application of a more concentrated ivermectin dose in a smaller volume (same final ivermectin dose rate), resulted in improved pharmacokinetic results, including greater Cmax and/or greater bicavailability (AUC) of thft i in another trial (also carried out as described in Example 2), a formulation according to the invention having 130g/L triciabendazole anc 7.5g/L ivermectin, and a formulation having 240g/L triclabendazoie and IC5/L ivermectin, were applied to animals over different area sizes on the backs of the animals (from the middle of the back towards the rump)r while maintaining the same dose rate for the active constituents. The results, shewn in Table 4, show that appiicaticn of the ivermectin and triciabendazole in a higher concentration "crmuiatlon applied over a smaller area makes the active agents more bioavailabie. Example 4 - Stability studies Samples of formulation A, the composition and preparation of which is described in Example 1, which contains sodium dodecyl sulphate, were stored at 4, 30 and 40°C in 250 mL high density polyethylene bottles sealed with screw caps, sampled at 1, 2, 3, 6 and 12 months, and tested for ivermectin and triciabendazole content. Triclabendazole and ivermectin content of the formulations was determined using validated stability indicating methods based on reversed phase HPLC with UV detection. The results, provided in Table 5, demonstrate the chemical stability of the formulation at accelerated storage conditions - effectively no degradation of the active components occurred even after 6 months storage at 40°C. After 12 months storage at 30°C there was stii! no measured degradation of the triciabendazoie and ivermectin components. After 12 month-s at 40°C there was less than 5% breakdown of the ivermectin component. Samples of formulation G, the ccnccsiticn and preparation of whicr. is described in Example 1, which contains sccium dcdecyi sulphate, were stored at 4. 30 and 40°C in 250 mL high density polyethylene bottles sealed with screw caps, sampled at 1, 2 and 3 months, and rested for ivermectin and trlciabendazole content. Triclabendazole and ivermsctin content of ir.e formulations was determined using validated stability indicating methods based on reversed phase HPLC with UV detection. The results, provided in Table 6, demonstrate the chemicaf stability of the formulation at accelerated storage conditions -effectively no degradation of the active components occurred even after 2 months storage at 30 or40°C. In another stability trial a number of substances were tested 'or their potential as a stabilizer for the formulations, ivermectin being unstable in iradequately stabilised formulations. The substances were each tested ai a concentration of 10.0 g/L, except phosphate buffers, in a formulation otrenvise ^aving the following composition (per Litre): Triclabendazole 120g Ivermectin 5.Cg Teric BL 3® 200g Benzyl alcohol 30g Water 150g Brilliant Blue FCF 0.16g Butyl Di Glysolv® approximately 485 mL (to volume) The samples were stored at 50°C in 250 mL nigh density polyethylene bottles sealed with screw caps, and sampled at 3 months, and tested for ivermectin and triclabendazole content. Triclabendazole and sverrnectin content of the formulations was determined using validated stability indicating methods based en reversed phase HPLC with UV detection. The data, provided :n ^able 7, illustrate the difficulty of stabilising the ivermeciin component of the formulation. From the stability data it was concluded that inclusion of anionic surfactants such as the linear alkyl sulphate sodium dcdecyl sulphate, or buffering agents such as one or more monobasic/ dibasic phosphates, or mixtures thereof, in the formulations of the invention significantly improve the stability of the ivermectin component. Example 5 - Efficacy studies Materials and Methods Cattle (typically Hereford or Hereford cross breed) with either natural or artificially infected burdens of fluke and nematodes were used in pen and field trials. They were allotted into treatment groups, each having similar mean weights and fiuke and nematode burdens. Experimental treatments were applied aiong the backline from the middle of the back towards the rump, using a commercially available backliner gun fitted with a plastic shroud to ensure correct delivery of the formulation according to the protocci. Efficacy was measured by either decrease in faecal egg counts over time or total parasite counts from gastrointestinal tracts and livers recovered after slaughter. The reported data are based on group arithmetic and/or grcup'geornetric means. Efficacy based on faecal worm egg counts were calculated as follows: % Efficacy = 100 [ 1 - (T2 Ci/ T^ C2)] where T, C, 1 and 2 refer to treated, control, pre-treatrnent and post treatment mean worm egg counts respectively. All other Efficacy data were calculated using the formula: %Efficacy= 100(C-T/C) where T and C refer to treated and control mean total worm counts respectively. For critical slaughter nematode efficacy studies, the animals were slaughtered at 14 or 21 days post treatment. For critical slaughter efficacy studies against ali stages of the liver fluke (artificially infested), the animals were slaughtered 100 days after treatment. Results Example 5.1 A critical slaughter pen efficacy thai (naturally acquired fluKe and nematodes) involved mixed sex Hereford and Hereford/Angus cross weared calves selected from 2 large commercial herds. The animals were randomly allocated to groups of 5 animals such that each group had a similar mean and range of Fasciola hepatica egg counts and body weights. Prior to treatment, animals were moved to a research feedlot to avoid further infection. At treatment the animals were weighed and treated with formulations of the triclabendazole + ivermectin pour on administered at different dose volumes and active concentrations. One group of 5 animals remained as untreated negative control. All animals were slaughtered 19 to 21 days post treatment, gastrointestinal tracts and livers recovered, and total worm and fluke numbers determined. Treatment formulations involving different concentrations of-active components and/or different excipients were tested, these formulations being as follows: Group 1 q or mUL Dosage rate (mq/kg) Triclabendazole 240g 12 Ivermectin 10.0g 0.5 Ecoteric T20® 200g PEG 200 30g Water - 150g Triethanolamine 0.74g Brilliant Blue FCF 0.16g Butyl diGlysolv® 491 mL Group 2 q or mUL Dosage rate (mg/kq) Triclabendazole 240g 24 Ivermectin 5.0g 0.5 Ecoteric T20® 20Og PEG 200 30g Water 150g Triethanolamine 1.27g Brilliant Blue FCF 0.16g Butyl diGlysolv® 494mL Group 3 Triclabendazole 240g 36 Ivermectin 3.33g 0.5 Ecoteric T20® 200g PEG 200 30g Water 150g Triethanolamine 1.12g Brilliant Blue FCF 0.16g Butyl diGlysolv® 498mL Group 4 Triclabendazole 240g 24 Ivermectin 5.0g 0.5 Ecoteric T20® 180g PEG 200 30g Water 150g Brilliant Blue FCF 0.16g Sodium dodecyl sulphate 20g Butyl diGlysolv® 480mL Group 5 q or mUL Dosage rate (mq/ko) Triciabendazole 240g 24 Ivermectin 5.0g 0.5 Ecoteric T20® 200g PEG 200 30g Water 150g Brilliant Blue FCF 0.16g Sodium dodecyl sulphate 20g Butyl diGlysolv® 480mL Group 6 Triciabendazole 240g 24 Ivermectin 5.0g 0.5 Ecoteric T20® 200g PEG 200 30g Water 150g Brilliant Blue FCF 0.16g Sodium dodecyl sulphate 20g Butyl diGiysolv® 316ml Ethylene glyco'diacetate i55mL The results, provided in Table 8, show that effective control of flukes and nematodes is achievable using a practical volume of an aqueous miceilar pour-on formulation of the present invention. The product was 100 % effective against adult Fasciola hepatica at dose rates of 12, 24 and 36 mg/kg triciabendazole and effective against nematodes at a dose rate of 0.5 mg/kg ivermectin. In this trial, an effective treatment of animals for endoparasites was achieved using 1mL/ 20kg of a formulation including 240g/L triciabendazole and 10.0g/L ivermectin (12mg/kg triciabendazole and 0.5 mg/kg ivermectin). Example 5.2 Two critical slaughter studies were designed to compare the efficacy of a formulation according to the invention (see below) against immature and adult stages of the liver fluke Fasciola hepatica, and naturally acquired roundworm infections in cattle. The efficacy of the triclabendazole +" ivermectin pour-on against immature and mature stages of Fasciola hepatica based on arithmetic mean was 70.5% and 99.2% respectively. Control of gastrointestinal strongyles by the test formulation (Group 5, Example 5.1, Table 8) as assessed using total worm counts at slaughter was 86% to 99.9% (arithmetic mean) for nematodes found in the abomasum, small and large intestines. Test formulation -described in Example 1.1, Formulation A Component g or mL/L Dose Rate (mg/kg) Triclabendazole 240g 24.0 Ivermectin 7.5 a 0.75 Ecoteric T20® 200g PEG 200 30g Water 150g Brilliant Blue FCF 0.16g Sodium dodecyl sulphate 20g Butyl diGlysoiv® approximately 475 mL (to volume) Example 5.3 Three field trials (faecal egg count reduction tests) were designed to determine the efficacy of the formulation described in Example 5.2 under field conditions. Sixty cattle were split into groups of 15, one of the groups remaining as an untreated control. Good efficacy of the formulation against Fasciola hepatica as assessed by a reduction in faecal egg counts as compared to the untreated controls of >90% (AM) was reported in all trials 14 days post treatment. Example 5.4 A field trial was designed to determine the efficacy of the following formulation against a mixed natural infection of adult and immature liver flukes and adult and immature nematode species. Component g /L Dose Rate (mg/kg) Triclabendazole 240g 24.0 Ivermectin 7.5 g 0.75 Ecoteric T20® 200g PEG 200 30g Water 150g Brilliant Blue FCF 0.16g Sodium doclecyl sulphate 20g Butyl diGlysolv® approximately 450 mL (to volume) Thirty (30) Angus cross and Limousin cross weaners, between 5 and 6 months of age, and weighing 112-242 kg, were selected from a larger commercial herd running at Armidale, New South Wales, Australia, on the basis of pre trial individual strongyle egg counts. The cattle grazed in open paddocks on a mixture of native and improved pasture with supplementary feed (buckwheat) provided on a daily basis. Over the treatment period at the Armidaie Saleyards cattle had ad-lib access to Lucerne hay. The cattle had not been exposed to any anthelmintic treatments for a period of three (3) months prior to the trial start date. Prior to treatment cattle were ranked from highest to lowest on individual pre trial liver strongyle faecal egg counts (Day -3), split into females and castrated males, blocked and randomly allocated to two (2) treatment groups such that the groups had a similar mean and range of strongyle faecal egg counts within the group. On day zero (0), all trial cattle were weighed and vaccinated with UltraVac 7 in 1 Vaccine (CSL Limited). The animals of Group 1 were left untreated, serving as negative controls. Group 2 was treated with the triclabendazole (240g/L) + ivermectin (7.5g/L) pour on formulation applied topically from the middle of the back to the base of the tail at a dose volume of 1mL/10kg. A prototype applicator which ensured the formulation was applied as a wide band was used for treatment. Faecal samples were collected from all trial cattle on day zero (0) and on days seven (7) fourteen (14) twenty one (21) and twenty eight (28) of the trial. Strongyle and liver fluke faecal egg counts and group bulk coprocultures for larval differentiation were performed on samples collected. Raw strongyle and fluke faecal egg counts were collated by treatment group and arithmetic means calculated. Geometric means were also calculated using transformed individual egg counts. Treatment efficacy, based on both arithmetic and geometric group means were calculated as follows: % Efficacy = (control group mean - treatment group mean)/control group mean x 100 Pre treatment Fasciola and strongyle faecal sgg counts were high, with a mean Strongyle faecal egg count of 802.7 e.p.g. (range 160-6120) and a mean Fasciola faecal egg count of 46 e.p.g. (range 0-1525) pre trial. Five genera of helminths were identified from group bulk coprocuitures including; Haemonchus spp., Trichostrongylus spp., Ostertagia spp,} Cooperia spp and Oesophagostomum spp.. Coooena sop made UD on average 70% of the bulk coproculture for the untreated controls from cay 0 to day 28. Group arithmetic and geometric mean Fasciola faecal egg counts over the duration of the trial -are presented in Table 9. Good control {>90% efficacy arithmetic mean, >97% efficacy geometric mean) of Fascioia hepaiica was achieved with the triclabendazole + ivermectin pour on, 7, 1^, 21 and 23 days pest treatment. Treatment efficacies based on arithmetic and geometric mean fluke faecai egg counts are presented in Table 10. Group arithmetic and geometric mean strongyie faecai egg counts over the duration of the trial are presented in Table 11. Efficacy of the triciabendazole + ivermectin pour on against strongyles was greater than 93% (geometric means) 7 and 28 days post treatment, and 89-8% and 83.5% 14 and 21 days post treatment. Efficacy based on arithmetic and geometric faecal egg counts are presented in Table 12. Example 5.5 A further field trial was designed to determine the efficacy ..of the formulation described in Example 5 4 against a mixed natural infecticn of aduit and immature liver flukes and adult and immature nematode species. Thirty (30) Angus and Angus cross heifers, between 12 and 14 months of age, and weighing 126-284 kg, were selected from a larger commercial herd running at Walcha, New South Wales, Australia, on the basis of pre trial individual strongyle egg counts. The cattle grazed in open paddocks on a mixture of native and improved pasture with ad-lib access to water. The cattle had not been exposed to any anthelmintic treatments for a period of three (3) months prior to the trial start date. Prior to treatment cattle were ranked from highest to lowest on individual pre trial liver strongyle faecai egg counts (Day -1), blocked and randomly allocated to .two (2) treatment groups such that the groups had a simiiar mean and range of strongyle faecal egg counts within the group. On day zero (0), all trial cattle were weighed. The animals of Group 1 were left untreated, serving as negative controls. Group 2 was treated with the triclabendazole (240g/L) + ivermectin (7.5g/L) pour on formulation applied topically from the middle of the back-te the base of the tail at a dose volume of 1mL/10kg. A prototype applicator which ensured the formulation was applied as a wide band was used for treatment. Faecal samples were collected from all trial cattle on day zero (0) and on days seven (7) fourteen (14) twenty one (21) and twenty nine (29) of the trial. Strongyle faecal egg counts and group bulk coprocuitures for larval differentiation were performed on samples collected. Raw strongyle egg counts were collated by treatment group and arithmetic means calculated. Geometric means were also calculated using transformed individual egg counts. Treatment efficacy, based on both arithmetic and geometric group means were calculated as fellows: % Efficacy = (control group mean - treatment group mean)/control group mean x 100 Pre treatment strongyie faecal egg counts were high, with a mean Strongyle faecal egg count of 288 e.p.g. (range 40-1320). Four genera of helminths were identified from group bulk coprocuitures at day zero (0) including: Haemonchus spp., Ostertagia spp., Cooperia spp and Oesophagostomurn spp.: Cooperia spp made up on average 70-80% of the bulk coprocuiture for the untreated controls from day 0 to day 29. Group arithmetic and geometric mean strongyle faecal egg counts over the duration of the trial are presented in Table 13. Efficacy of the triclabendazole + ivermectin pour on against strongyies reached a maximum 84% reduction in egg counts (arithmetic means) 7 days post treatment, and 78%, 59% and 63% 14, 21 and 29 days post treatment. Treatment efficacies based on arithmetic and geometric strongyle egg counts are presented in Table 14. Example 5,6 A dose evaluation critical slaughter study was designed to compare the pharmacokinetics and efficacy of the developmental topical triclabendazoie + ivermectin formulation described in Example 5.4 (240g/L triclabendazoie and 7.5 g/L ivermectin), and the developmental topicai triciabendazole + ivermectin formulations of formulae F (240 g/L triclabendazoie and 10 g/L ivermectin) and G (240 g/L triciabendazole and 15 g/L ivermectin) described in Examples 1.6 and , 1.7 respectively against a mixed natural infection of gastrointestinal strcngyies, so as to determine the optimum concentration of ivermectin in the formulation for effective control of Cooperia spp as well as the other nematodes. Fifty (50) Hereford and Angus cross steers, aged between five to six (5-6) months and weighing between 102-164kg at treatment, were selected from a larger mob at Casino on the North Coast of NSW; Australia on the basis of pre trial individual strongyle faecal egg counts. The cattle were relocated to "Kirby", Armidale NSW, Australia twenty days prior to treatment and grazed In open paddocks on a mixture of native and improved pastures. Trial cattle were fed Lucerne hay while they were held in the Armidale Saleyards (day 0 through to day 2). The cattle had not been exposed to triciabendazole or ivermectin for a period of three (3) months prior to the trial start date and had no known resistance by gastrointestinal strongyles to macrocyclic lactcnes. Five (5} days prior to treatment faecal samples were collected from each animal for individual faecal egg counts and bulk coproculture. Triplicate blood samples were collected for triciabendazole and ivermectin plasma analysis: One (1) day prior to treatment Twenty five (25) trial cattle were re-located to the Armidale Saleyards, ranked from highest to lowest according to individual egg counts (day -5), sequentially blocked and allocated at random to five (5; groups of five (5) animals, such that each group had a similar mean and ranee of strnnnvi** fa^ooi egg counts. The animals of Group 1 were left untreated, serving as negative controls. Group 2 was treated with the 240g/L trictabendazole + 7.5g/L ivermectin pour on formulation. Group 3 was treated with the 240g/L triclabendazole + 10.0g/L ivermectin pour on formulation. Group 4 was treated with the 240g/L triclabendazole + 15.0g/L ivermectin pcur on formulation. Ail formulations were applied topically from the middle of the back to the base of the tail at a dose volume of 1mL/10kg (according lo a dose break table). A prototype applicator which ensured the formulation was applied as a wide band was used for treatment. Two (2) day after treatment all cattle were re-located from the Armidale Saleyards to the Kirby feedlct for the remainder of the trial. Faecal samples were collected frcm each individual animai in all groups five {5} days prior to treatment then nine (9) for Individual faecal egg counts and coprocultures pre and post treatment. Ail trial cattle were sacrificed 13, 14 and 15 days post treatment. Faecal samples, abomassa, small intestine and large intestine were collected from each anima! for faecal egg counts, group coprocultures and total worm counts (adult and immature). Treatment efficacy was assessed by comparison of group arithmetic and geometric mean total worm counts (as described in Examples 5.4 and 5.5) by nematode species and strongyle faecal egg counts following sacrifice and organ recovery. Pre treatment egg counts were generally high ranging frcm 480-1480 eggs per gram (e.p.g.) of faeces. At 13 - 15 days post treatment, animals treated with the pour-on formulations produced a reduction in egg counts when compared to the untreated controls of between 73% (240 g/L triclabendazoie plus 7.5 g/L ivermectin) to 98% (240 g/L triclabendazole plus 15.0 g/L ivermectin) (arithmetic means) and between 94 % and > 99 % respectively (geometric means). (Table 15). At necropsy, seven (7) genera of heirninths were recovered from the gastrointestinal tract of the control cattle approximately 80% of which consisted of adult, immature and L4 stages of Cooperia spp. Other gastrointestinal nematodes identified include Trichuris spp, Nematodirus spp. Oesophagosornum spp. Trichostrongylus spp, Haemonchus spp and Ostertagia spp which each made up approximately 5% or less of the total count. Total worm count data indicated that the small intestinal worms, Coopeha spp. and adult Nematodirus spp,t were the most difficult species to remove following treatment. Efficacy increased with increasing concentration of ivermectin in the formulation. The 240 g/L triclabendazole plus 15.0 g/L ivermectin formulation efficacy against adult and immature stages of small intestinal nematodes (Trichostrongylus sppt Cooperia spp) was greater than 90% (arithmetic and geometric means) and greater than 99% (geometric means) with the exception of adult Nematodirus [49.1% (arithmetic means) and 93 % (geometric means)]. Greater than 95% efficacy (geometric and arithmetic) was achieved against adult and immature stages of abomasal nematodes (Haemonchus 3pp, Ostertagia ostertagia, Trichostrongylus axef; and large intestinal nematodes (Oesphagostomum sppr Trichuris spp). Greater than 95% efficacy (arithmetic and geometric means/ was achieved by the 240g/L tridabendazoie plus 7.5g/L ivermectin and the 240g/L triclacendazoie plus 10g/L ivermectin formulations against abomasal nematodes (with the exception of fourth stage Ostertagia larvae in cattle treated with the 240g/L triclabendazole plus 10g/L ivermectin formulation ). Efficacy against small intestinal nematodes increased from 57.7% to greater than 99.9% with increased concentration of ivermectin. Triplicate blood samples were also collected five (5) days prior to treatment then 1, 3, 5 and 7 days post treatment from animals in groups 2, 3, 4 and 5 for triclabendazole and ivermectin analysis. Plasma ivermectin C^x and AUC values increased relative to the concentration in the formulation - Table 17. Summary: For a given dose volume (1mL per 10 kg bcdyweight), increasing the concentration of ivermectin in the formulation increased the plasma concentration and efficacy. Nematode efficacy of the 240 g/L triclabendazole plus 15.0 g/L ivermectin was higher and more consistent than the corresponding formulations containing 7.5 and 10,0 g/L ivermectin, especially against the hard to control small intestinal worms, Cooperia spp and Nematodirus spp. Industrial Appticability The formulations of the invention can be readily used to treat, control or prevent disease caused by, and/or infestations of, endo-parasites such as liver fluke and nematodes as well as ecto-parasites, particularly in treating, controlling and/or preventing liver fluke and nematode infestations in sheep or cattle, particularly cattle. It will be appreciated that, although specific embodiments of the invention have been described herein for the purpose of illustration, various modifications may be made without deviating from the spirit and scope cf the invention as defined in the following claims. What is claimed is: 1. An aqueous micellar formulation comprising a first active agent, selected from water insoluble benzimidazoles, salicylanilides and active derivatives or salts thereof, in combination with a second active agent, selected from macrocyclic Iactones or active derivatives or salts thereof, said formulation being for topical application to animals for the control of internal parasites and also comprising, per litre of formulation: from about 100g to about 400g veterinary-acceptable surfactant(s); from about 200g to about 750g veterinary-acceptable water-miscibte solvent(s); and from about 50g to about 350g of water. 2. A formulation according to Claim 1, wherein said surfactant is selected from polyoxyethylene sorbitan fatty acid esters or combinations thereof. 3. A formulation according to Claim 2, wherein said surfactant is polyoxyethylene (20) sorbitan monolaurate. 4. A formulation according to any one of Claim 1, wherein said water- miscible solvent is selected from ethanol, isopropanol, benzyl alcohol, glycoi ethers, liquid polyoxyethylene glycols, or a mixture of at least two of these solvents. 5. A formulation according to Claim 4, wherein one or more of the glycoi ethers are selected from alkylene ordialkylene glycoi monoalkyl ethers. 6. A formulation according to Claim 5, wherein said one or more of glycoi ethers are selected from propylene glycoi monomethyl ether, diethylene glycoi monoethyl ether, and diethylene glycoi monobutyl ether. 7. A formulation according to Claim 4, comprising a glycoi ether and a liquid polyethylene glycoi as water-miscible solvents. 8. A formulation according to Claim 7, wherein the polyethylene glycoi is PEG 200. 9. A formulation according to Claim 1, further comprising from about 5g to about 50g per litre of formulation of a stabilizer selected from linear anionic surfactants, buffering agents and mixtures thereof. 10. A formulation according to Claim 9, wherein said stabilizer is selected from linear alkyl sulphates, linear alkyl benzene sulphonates, and phosphates, or mixtures thereof. 11. A formulation according to Claim 10, wherein said stabilizer is sodium dodecyl sulphate. 12. A formulation, according to Claim 1t comprising about 100g tc about 300g surfactant per litre of formulation. 13. A formulation according to Claim 1, comprising from about 3Q0g tc about 650g water-miscible solvent(s) per litre of formuiation, 14. A formulation accordina to claim 1, wherein said formuiation comorises from about 10g to about 100g per litre of formulation of a liquid polyeihyiene glycoi as a water-miscible solvent. 15. A formulation according to Claim 13, comprising about 450g tc about 550g glycoi ether(s) selected from alkylene or dialkylene giycoi monoalkyi ethers, and about 20g to about 50g of a liquid polyethylene giycoi as the one cr more water-miscible solvents per litre of formulation. 16. A formulation according to Claim 1, comprising about 150g water per litre of formulation. 17. A formulation according to Claim 1, comprising from about 120g to about 300g benzimidazole, or a derivative thereof, per litre of formulation. 18. A formulation according to Claim 16 or Claim 17, wherein said first active agent is triclabendazole. 19. A formulation according to Claims 1, comprising from about 7.5g to about 20g macrocyclic lactone per litre of formulation. 20. A formulation according to Claim 19, comprising about 15g macrocyclic lactone per litre formulation. 21. A formulation according to Claim 19 or Claim 20, wherein said macrocyclic lactone is ivermectin. 22. A formulation according to Claim 1, comprising, per litre of formuiation: about 180g to about 240g benzimidazole; about 7.5g to about 20g macrocyciic lactone or an active derivative or salt thereof; about 150g to about 250g polyoxyethylene (20) sorbitan mortoiaurate; about 450g to about 550g diethylene giyco! monobutyi ether; about 20g to about 50g PEG 200; about 10g to about 30g sodium dodecyl sulphate; and about 100g to about 200g of water. 23. The formulation of Claim 22 which comprises about 240g triclabendazole and about 15g ivermectin per litre. 24. A method of treating or preventing a diseased or parasite-infested state in a mammal, comprising topically administering to said mammal a micellar formulation according to Claim 1 or Claim 22, wherein said disease or parasite- infested state comprises a liver fluke infection or infestation, a nematode infection or infestation, or both a liver fluke and a nematode infection or infestation in a mammal. 25. A method according to Claim 24, wherein said mammal is selected from cattle, sheep, goats, pigs and horses. 26. A method according to Claims 24, wherein said topical application comprises application of the formulation in a band along the lower portion of the back of the mammal. 27. A method according to Claim 26, wherein the formulation is applied to the mammal over as small a region as possible, while avoiding run-off of the • formulation so as to maximise the concentration of active agents per cm2 of animal surface. 28. A method according to Claim 26, wherein the band of formulation is applied starting from the thoracic vertebrae and proceeding towards the rump of the animal, and from about 18mg to about 24mg triclabendazole and from about 0.75mg to about 2mg ivermectin are applied per kilogram animal. 29. The method of Claim 28, wherein about 24mg tricfabendazole and about 15mg ivermectin are applied per kilogram animal.

Full Text

Topical Parasiticide Formulations And Methods Of Treatment
Technical Field
This invention relates to formulations for administration of benzimidazoles or salicylanilides with macrocydic lactones to livestock for the control of endo-and/or ecto-parasites, methods for dosing livestock with such formulations, and methods for controlling and/or preventing diseases or parasite infection in livestock.
Background Art
A number of formulations containing active components, such as therapeutic, prophylactic and/or bioactive substances, for the treatment and/or prophylaxis of diseases or parasite infection in livestock, are known. Such formulations include tablets and solutions for oral administration, injectable solutions, treated collars and ear-tags, and topical means, including pour-on and spot-on formulations.
Many of the early such formulations were intended for topical treatment/prophylaxis of ectoparasite-related conditions, designed to spread the active component over the skin and/or hair surfaces of the animal, not to administer the active component(s) to the bloodstream of the animal being treated. More recently, endoparasiticide pour-on formulations for delivery of particular active agents, including macrocydic lactones, to the bloodstream of domestic animals, such as sheep and cattle, have been developed, and these have the advantage over other administration forms, such as oral drenches and injection, of being easily applied to animals in a relatively-accurate amount.
Known pour-on and spot-on formulations for endoparasiticide treatment generally utilise a non-aqueous delivery system for administering active components to animals, since the active ingredients of interest were substantially water-insoluble (particularly macrocydic lactones, levamisole base, benzimidazoles), and it was believed that dissolution of the parasiticide was necessary in order for the parasiticide to become systemically absorbed.
Commercial ectoparasiticide products are available as both solvent-based and aqueous-based formulations. Water-insoluble actives have been formulated as aqueous suspension pour-on formulations, e.g., deltamethrin (a synthetic pyrethroid) for the treatment of lice on sheep (Clout S®, Schering-Plough) and

cattle (Coopers® Easy Dose, Schering-Plough), and diflubenzuron (insect growth regulator, or IGR) for lice on sheep (Magnum IGR®, Schering-Plough). These treatments are characterised by low levels of actives found in tissues following treatment, reflecting little penetration of active through the skin layer. Solvent-based formulations containing the water-insoluble IGR, triflumuron (e.g., Zapp®, Bayer) for lice control on sheep are also available. At an equivalent dose rate to the aqueous-based formulations, these solvent-based formulations lead to higher tissue residues immediately after treatment. This supports the assertion that a water-insoluble active will be more easily systemically absorbed if it is solubilized in the formulation.
By 'water-insoluble1, it is meant that the water solubility is insufficient for an effective amount of an endoparasiticide to be dissolved in a commercially-viable dose of a water-based pour-on formulation. Practically, a dose of pour-on formulation should not be much more than t.0mL/10kg bodyweight (for ease-of application and to prevent runoff). At this rate, a 500kg beast would receive a 50mL dose, therefore, a 2.0mL/10kg dose is not practical, as many animals weigh much more than 500 kg.
Benzimidazoles and macrocyclic lactones are important classes of agents for the treatment or prevention of a number of important endoparasites of livestock, including acute or chronic liver fluke disease, best recognized in sheep and cattle, caused by the liver parasite Fasciola hepatica, and nematodes such as the Cooperia. Ostertagia, and Trichostrongylus species.
Triclabendazole is a particularly effective benzimidazole, and is the most effective drug currently available against all stages of Fasciola hepatica, destroying the early immature and immature fluke migrating through the liver, as well as the adult fluke in the bile duct.
Salicylanilide compounds form another important class of agents for control of endoparasites, particularly Fasciola hepatica, and nematodes, such as Haemonchus species. The salicylanilide oxyclozanide is effective against adult liver fluke (Fasciola hepatica) and immature paramphistones migrating in the intestine of cattle and the young flukes in the rumen and reticulum. Oxyclozanide is highly insoluble in water and is administered to animals in an aqueous suspension formulation by oral dosing.

Commercial endectocide pour-on products containing the avermectins, ivermectin (Paramax®, Schering-Plough, Ivomec® Cattle Pour-On, Merial), moxidectin (Cydectin®,. Fort Dodge) and doramectin (Dectomax®, Pfizer), are currently available for treatment of cattle for the control or prophylaxis of a number of endo- and ectoparasites, such as lice, flies and ticks. These formulations, however, require significantly higher administration rates of the active component, as compared to oral drenching techniques, typically at least two times the oral drenching rates, in order to achieve effective biocd concentrations of the active ingredient in the animal, and to achieve the same efficacy of treatment. For example, Ivermectin oral solution ;or cattle (!vorneci?) Oral Solution for Cattle, Merial, registered in New Zealand) has a dose rate of 200 micrograms ivermectin/kg bodyweight, whereas ivomec® Cattle Pour-On has a dose rate of 500 micrograms ivermectin /kg bGdyweight.
Treatment of liver fluke in cattle with anthelmintics, such as triciabendazole is generally carried out by oral drenching with a commercial product, for example Fasinex® 120 (120 g/L triclabendazoie, Novartis), as well as by injection (ivomec® Plus Antiparasitic Injection for cattle, Merial, which also controls adult liver fluke).
Pour-on or spot-on formulations of salicylanilide derivatives are not currently available, usually being administered to livestock by oral drench.
It would be highly desirable, in order to provide broad-scectrurr: protection against endoparasites and ectoparasites, through efficient deliver/ of water-insoluble compounds, such as benzimidazoles or saiicyianiliGes, in combination with macrocyclic iactones to the bloodstream of animals by a single, convenient topical application, rather than by oral administration.
By "efficient delivery", it is meant that the active agent is administered at a rate approximating oral dosage rates, up to about twice normal oral dosage rates, to give effective blood concentrations and equivalent efficacy-International Publication No. WO00/61068 (PCT/N200/00053) discloses triciabendazole, optionally in combination with a macrocyclic Sactone, dissolved in at least one solvent, preferably administered as a pour-on formulation for control of liver fluke. Efficacy data supplied (based on a !ow natural infection fluke challenge, mean of 20), however, shows that the formulation was applied at 2.5 times the dose of a standard oral drench rate to give equivalent efficacy. Also, two of the solvents described, xylene and toluene, are highly flammable. The reported triciabendazole content of the formulation, after 345 days storage at ambient temperature, is 7.5% lower than the initial assay, although there is no

decrease in the abamectin content. Solvent-based formulations of ivermectin can break down rapidly unless suitably stabilized.
A solvent-based, topically-administered formulation of the salicylanilide closantel with the macrocyclic lactone ivermectin, for the control of parasites, has been described in U.S. Patent No. 6,340,672. The maximum concentration of active agents described in the examples of this document is 0.5%w/v for ivermectin and 5%w/v for closantel. At these concentrations, unacceptably large volumes of the formulations (from a practical viewpoint) would need to be poured onto the animals in order to achieve effective blood concentrations of the active agents.
WO 00/74489 (PCT/NZOO/00087) discloses biocidal compositions, including pour-on formulations which are water-in-oil (soyabean) emulsions stabilized with an emulsifying agent. The formulations comprise the water-soluble anthelmintic, levamisole (as the hydrochloride salt), and a macrocyclic lactone (abamectin or ivermectin), optionally in combination with a benzimidazole (oxfendazole). Only low levels of benzimidazole are present in the formulations disclosed in this document (up to 5%w/v oxfendazole in an oral drench formulation), and only one pour-on formulation comprising a benzimidazole (2-.26%w/v oxfendazole) and a macrocyclic lactone (0.1%w/v abamectin) is disclosed. Whilst this pour-on formulation is described as delivering the levamisole to the bloodstream of cattle with efficiency similar to oral drench administration, the macrocyclic lactones and benzimidazoles were delivered with low efficiency and a commercially-unpractical volume of this formulation would be required to be applied to animals in order to achieve effective blood concentrations of these actives.
Objects of the Invention
It is an object of this invention to provide a topical formulation capable of efficient delivery of a benzimidazole or salicylanilide, in combination with a macrocyclic lactone, to the bloodstream of an animal for broad-spectrum control of endoparasites, such as liver fluke and nematodes, in animals, such as sheep and cattle, with-a-single, easily-applied topicalformulation.
Summary of the Invention
It has now been surprisingly found that a benzimidazole or a salicylanilide, in combination with a macrocyclic lactone, may be formulated into a stable aqueous

micellar composition which, when applied topically to an animal, efficiently delivers the desired active constituents to the bloodstream of the animal, and provides effective protection against infestation by endoparasites such as liver fluke and nematodes.
Thus, the present invention provides an aqueous mlcaiiar formulation comprising a first active agent selected from benzimidazoles, salicylanilides and active derivatives or salts thereof, in combination with a second active agent selected from macrocyclic lactones or active derivatives or salts thereof, saia formulation being for topical application to animals for the control of internal parasites anc also comprising, per litre of formulation;
from about 100g to about 400g veterinary-acceptable surfactant(s);
from about 200g to about 750g veterinary-acceptable water-rniscible
solvent(s); and
from about 50g to about 350g water.
Surprisingly, it has also been found that the stability of aqueous miceilar formulations of the invention may be improved by inclusion of a stabilizer selected from anionic surfactants, such as sodium dodecyl sulphate (SDS), and/or buffering agents, such as soluble phosphates and/or dibasic phosphates.
Thus, in a preferred aspect of the invention, the aqueous micellar formulation comprises a stabilizer selected from anionic surfactants or buffering agents, or mixtures thereof. Preferably the stabilizer is a linear alky! sulphate, such as sodium dodecyl sulphate, or one or more phosphates/dibasic phosphates, or mixtures thereof.
In a preferred embodiment, there is provided an aqueous micellar formulation comprising a benzimidazole in combination with a macrocyclic lactone, said formulation being for topical application to animals for the control of internal parasites and also comprising, per litre of formulation:
about 100g to about 300g poiyoxyalkyler.e sorbitan fatty acid ester
surfactant;
about 300g to about 650g alkylene glycol ether selected from alkylene
or dialkylene glycol monoalkyi ethers or combinations thereof;
about 10g to about 100g polyethylene glycci;
about 5g to about 50g stabilizer; and

about 50g to about 350g water.
in a particularly preferred aspect of this embodiment, the formulation comprises, per litre formulation:
about 180g to about 240g benzimidazole;
about 7.5g to about 20g macrocyciic lactone or an active derivative or
salt thereof;
about 150g to about 250g polyoxyethyiene (20) sorbitan monoiaurate;
about 450g to about 550g diethylene glycol monobutyl ether;
about 20g to about 50g PEG 200;
about 20g sodium dodecyi sulphate; and
about 100g to about 200g water.
The invention also provides a,method of treating or preventing a diseased or parasite-infested state in a mammal, comprising topically administering to said mammal a micellar formulation according to the instant invention.
Typically, the diseased or infested state is related to liver fluke, such as caused by Fasciola hepatica, and nematodes, such as Cooperia, Ostertagia, Trichostrongylus and Haemonchus species, or combinations thereof.
Even more typically, the diseased or infested state to be treated or prevented is a disease or infested state of cattle or sheep, more typically cattle.
Surprisingly, it was found that the location and size of the region of topical administration of the formulations was important for efficiency of permeation of the active agents across the skin into the bloodstream.
Thus, in a preferred aspect of the methods of treatment, the formulation is applied in a band along the lower portion of the back of the mammal.
Preferably, so as to maximise efficiency of delivery of the active agents to the bloodstream of the animal, the formulation is applied to the animal over as small a region as possible while avoiding run-off of the formulation/so as to maximise the concentration of active agents per cm2 of animal surface.
In another preferred aspect of the methods of treatment, the formulation is sprayed onto the back of the animal.

Where the animals to be treated are cattle, the formulation is preferably applied to the flat part of the back, typically the last third of the animal, and most typically starting from the thoracic vertebrae and proceeding towards the rump of the animal. Typically, about 24mg benzimidazole/salicylanilide and about 1.5mg macrocyclic lactone are applied per kilogram of animal. Typically, the band of formulation applied will be from about 5cm to about 15cm wide and, depending on the size of animal, about 20cm -to 40cm long, and even more typically, the formulation is sprayed onto the back of the animal and the height of the source of spray relative to the back of the animal is maintained at about 5cm to 10cm.
As used herein, the term "treating or preventing", refers to any and all uses which remedy or prevent a diseased or infested state or symptoms, or otherwise prevent, hinder, retard, or reverse the progression of disease/infestation or other undesirable symptoms in any way whatsoever. 'Infestation11 and corresponding derived terms relate to infestation by endo- and/or ecto-parasites.
An "effective amount", as referred to herein, includes a non-toxic therapeutic or prophylactic amount of an active agent adequate to provide the desired effect. The "effective amount" will vary from subject-to-subject, depending on one or more of a number of factors amongst, for example, the particular agent being administered, the type and/or severity of a condition being treated, the species being treated, the weight, age and general condition of the subject and the mode of administration. For any given case, an appropriate "effective amount" may be determined by one of ordinary skill in the art using only routine experimentation. Also, extensive literature is available for many known active agents through, for example, manufacturers' catalogues, the Internet, scientific journals and patent literature, including effective amounts for administration to target animals.
Typically, "effective amount" refers to an amount of active agent sufficient to result in one or more or the following: recession/reduction in the extent of a disease/infestation; inhibition of disease/infestation growth or progression; cessation of disease/infestation growth or progression; prevention of disease/infestation; relief of disease/infestation-imposed discomfort; or prolongation of life of the animal having the disease.
As used herein, the term "about", in the context of concentrations of components of the formulations, typically means +/- 5% of the stated value, more typically +/-4% of the stated value, more typically +/- 3% of the stated value, more typically, +/- 2% of the stated value, even more typically +/- 1% of the stated value, and even more typically +/- 0.5% of the stated value.

As ufeed herein, the term "comprising" means Including principally, but not necessarily solely". Variations of the word "comprising", such as "comprise" and "comprises", have correspondingly similar meanings.
Detailed Description of the Invention Aqueous Micellar formulations
The present invention is based on the finding that hydrochcbic active agents, such as benzimidazoles and salicylanilides, may be orovided in a formulation for topical administration along with therapeutic amounts of a macrocyciic iactone for efficient delivery of both the benzimidazole/salicylanilide and the macrocyciic Iactone to the bloodstream of the animal for effective control of encoparasites such as liver fluke and nematodes. It has also been found by the present investigations that efficiency of delivery of the active agents to the bloodstream of a mammal is affected by the topical location of application of the formulation, minimising the area of the skin to which the active agents are applied and/or use of formulations having elevated concentrations of the active agents. The formulations of the present invention surprisingly allow for elevated concentrations of benzimidazole(s) or saiicylanilide(s), in combination with one or more macrocyciic lactones, to be provided in a single composition for efficient delivery of the active agents to the bloodstream of a mammal by topical administration.
The formulations are aqueous micellar compositions, comprising elevated levels of the active agents and, per litre of formulation:
from about 100g to 400g veterinary-acceptable surfactant(s);
from 200g to 750g veterinary-acceptable water-miscible solvents); and
from 50g to 350g water.
Advantageously, the surfactant is non-ionic and selected from scrbitan esters, polyoxyalkylated sorbitan esters, polyoxyalkylated alkyi ethers, polyoxyalkylated fatty alcohols, polyoxyalkylated fatty acids, polyalkyiene glycol esters, polyoxyalkylated derivatives of castor oil, polyglycerol esters, copoiymers of ethylene oxide and propylene oxide; amine ethoxylates; alkyi phenol ethoxylates; alkyi polysaccharides; or combinations thereof, although the surfactant may also be, or include, anionic surfactants seiected from linear alkylbenzene sulphonates; C12-to-C16 alcohol sulphates; C12

alkoxypolyethanoxy sulphates; alkyl phosphates and phosphonates or combinations thereof.
Preferred surfactants are selected from polyoxyalkylated fatty alcohols and polyoxyethylene sorbitan- or sorbitol- fatty acid esters or combinations thereof, and particularly preferred are polyoxyethylene sorbitan- or sorbitol- fatty acid esters.
Generally, the polyoxyalkylene sorbitan- or sorbitol- fatty acid esters are polyoxyethylene sorbitan fatty acid esters. Poiyoxyethylene sorbitan fatty acid esters such as those of the Ecoteric® series (Huntsman) are preferred. Especially preferred polyoxyethylene sorbitan fatty acid ester surfactants are polyoxyethylene (20) sorbitan monolaurate (Ecoteric® T 20) and polyoxyethylene (20) sorbitan monooleate (Ecoteric® T 80),
Typically the polyoxylated fatty alcohols are poiyalkylene oxide derivatives of natural or synthetic alcohols, and those of synthetic alcohols, such as provided by the Teric® series (Huntsman) are preferred. Especially preferred is Teric® BL8.
Generally, the amount of surfactant used in the formulation ranges from about 100g/L to about 400g/L, typically about 100g/L to about 300g/L, more typically about 150g/L to about 300g/Lf even more typically about 150g/L to about 250g surfactant, and even more typically about 175g/L to about 225g/L preferably about 200g/L, based on the total amount of formulation.
The water-miscible solyent(s) may be selected from: ethanol; isopropanol; benzyl alcohol; glycol ethers; liquid polyoxyethylene glycols; or a mixture of at least two of these solvents.
Particularly-preferred water-miscible solvents are the glycol ethers, and particularly in combination with a liquid polyethylene glycol. A particularly-preferred polyethylene glycol is PEG 200.
Generally, the glycol ethers are alkylene glycol alkyl ethers, including ethylene glycol monoethyl ether, ethylene glycol monomethyl ether, propylene giycol monomethyl ether (Glysolv PM®, Huntsman), dipropylene glycol monomethyl ether, diethylene glycol monoethyl ether (Ethyl di Glysolv®, Huntsman),

diethylene glycol monobutyl ether (Butyl di Glysoiv® or Butyl Digol®, Huntsman), and diethylene glycol diethyl ether and the like. Particularly preferred glycol ethers are diethylene glycol moncethyl ether (Ethyl di Glysoiv®) and/or dierhylene glycol monobutyl ether (Butyl di Glysoiv® or Butyl Digol®).
Generally, the amount of water-miscibie solvent(s) used in the formulation ranges from about 200g/L to about 750g/L, typically about 300g/L to about 650g/L more typically about 300g/L to about 550g/L and even more typically about 400g/L to about 550g/L, preferably about 45Og/L to about 550g/L, based on the tcta! amount of formulation, but will vary depending on the particular soivent(s) used and the amount of active agents to be included in the micellar formulation.
Where, according to a preferred aspect of the invention, the formulation comprises both a glycol ether and a liquid polyethylene giycoi, the amount of glycoi ether used in the formulation typically ranges from about 350g/L to about 650g/L, more typically about 400g/L to about 600g/L and even mere typically about 450g/L to about 550g/L, preferably about 450g/L to about 5QQg/L based on the total amount of formulation. The amount of liquid polyethylene glycol used in the formulation typically ranges from about lOg/L to about tOOg/l, more typically from about 20g/L to about 70g/L, even more typically from about 20g/L to about 50g/L, preferably about 30g/L, based on the total amount of formulation.
Generally, the amount of water used in the formulation ranges from about 50g/L to about 350g/L, typically about 100g/L to about 300g/L more typically about 100g/L to about 250g/Lt and even more typically about 150g/L to about 200g/L, preferably about 150g/L, based on the total amount of formulation.
Examples of suitable benzimidazoles include: 2-(4-thiazoIyl)-1H-benzimiclazole, known as thiabendazole; [5-(propylthio)-1H-benzimidazol-2-yl]carbamic acid methyl ester, known as albendazcie; [5-(propylsulfinyl)-1 H-benzimidazol-2-yl]carbamic acid methyl ester known as albendazole sulfoxide or albendazole oxide; [2-(4-thiazolyl)-1H-benzimidazol-5-yl]carbamic^ acid 1-methylethyl ester, known as cambendazofe; [5-(phenylthio)-1H-benzimidazol-2-y!]carbamic acid methyl ester, known as fenbendazole; (5-benzoyl-1H-benzimidazol-2-yi)carbamic acid methyl ester, known as mebendazcle; [5-(phenylsulfinyi)-1H-benzimidazoi-2-yl]carbamic acid methyl ester, known as is oxfendazole; (5-propoxy-1H-benzimidazol-2-yI)carbamic acid methyl ester, known as oxibendazole; [5-{N-

butyl)-1H-benzimidazol-2-yl]carbamic acid methyl ester known as parbendazole; methyl 5-cyclopropylcarbonyl-1H-benzimidazol-2-ylcarbamate known as cyclobendazole; methyl 5-(4-fluorobenzoyl)-1H-benzimidazol-2:ylcarbamate known as fiubendazole; S-chloro-e^.S-dichlorophenoxy^-Cmethylthio)-benzimidazole known as triclabendazole; and [5-(4-fIuoro-phenylsulfonyloxy)-1H-benzimidazol-2-yl]carbamic acid methyl ester known as luxabendazole.
The benzimidazole antiparasitic agents are active against one or more of Haemonchus, Ostertagia, Trichostrongylus, Nematodirus, Cooperia, Bunostomum, Strcngyloides, Trichuris, Oesophagostomum, Chabertia, Dictyocaulus, Mcniezia and Fasciola in sheep and against Haemonchus, Ostertagia, Trichostrongylus, Nematodirus, Cooperia, Bunostomum, Capillaria, Strongyloides, Trichuris, Oesophagostomum, Chabertia, Dictyocaulus, Moniezia and Fasciola in cattle.
Particularly preferred as benzimidazole is triclabendazole.
Examples of suitable salicylanilide compounds for use in the control of Fasciola
and Haemonchus species in livestock include oxyclozanide (3,3\5,5\6-
pentachlcro-2t-hydroxysalicylanilide), closantel (S'-chloro^'^-chloro-alpha-
cyanobenzyl)-3,5-diiodosalicyl-o-toluidide), rafoxanide (3'-chlon>4'-(4-
chlorophenoxy)-3,5-diiodosalicylanilide), and niclosamide (2\5-dichloro-4'-nitrosalicylanilide), as well as clioxanide, brotianide and bromoxanide.
Salicylanilide derivatives, and their use for control of endoparasites in livestock,
has been described in, for example, U.S. Patent numbers 3,914,418; 3,927,071;
3,989,826; 4,005,218; and 4,025,647, "Veterinary Anthelmintics", by J.H.
Arundel, University of Sydney, Post Graduate Foundation in Veterinary Science,
and the Merck Veterinary Manual
(http://www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/191415.htm).
Oxyclozanide is a particularly preferred salicylanilide for use in formulations according to the invention.
Typically, the macrocyclic iactone(s) is/are selected from the group consisting of ivermectin (22,23-dihydroavermectin Bi described in EP 295117), abamectin, avermectin Aia, avermectin A1bi avermectin A2a, avermectin A2b, avermectin B-ia, avermectin Bib, avermectin B2a, and avermectin B2t>. Also typically, the

4
macrocyclic lactone may be selected from active derivatives of the naturally occurring avermectins, such as derivatives which have a group at the 25-
substituent other than the isopropyl or (S)-sec-butyl groups, as set out in European patent applications 0214731, 0284176, 0308145. 0317148, C335541 and 0340832. Also, typically, the rnacrccyciic lactone of the first aspect of the invention can include moxidectin (and derivatives disclosec n European patent publication No. 259779A), doramectin and its analogues (described ;n European patent publication No. 02147318), selamectin. eprinomectin, milbemycin including milbemycin oxime, milbemycin D (Antibiotic S41D" and its analogues (described in U.S. Patent No. 3,950,360} and nemadectirs (described :r European patent publication No. 170006A).

01
i he macrocyclic lactone antiparasitlc agents are active against one or .-nore Haemonchus, Ostertagia, Trichcstrohgylus, Nema icdirus, Cooperia; Strongyloides, Trichuris, Oesophagcsiomum, Chabertia and Dicryocauius in sheep and against Haemonchus, Ostertagia, Trichostrongylus, Nematodirus. Cooperia, Oesophagostomum and Dictyocaulus in cattle.
Particularly preferred as a macrocyclic lactone is ivermectin.
Generally, where present, the amount of benzimidazole used in the formulation ranges from about 90g/L to about 360g/l, typically about SCg/L to about 300g/L, more typically about 150g/L to about 300g/L, even more typically about 180g/L to about 270g/L, and even more typically about 180g/L to about 240g/L, preferably about 240g/L, based on the total amount of formulation. Generally about 9mc to about 36mg, typically about 9mg to about 30mg, more typically about 15mg to about 30mg, even more typically about 18mg to about 27iTig1 and even more typically 18mg to about 24mg, preferably about 2^mg of benzimidazole per Kg bodyweight are applied topically to a mammal in a single dosage.
Generally, where present, the amount of saHcylaniiide used in the formulation ranges from about 125g/L to about 50Og/L, typically abcut 160g/L to about 375g/L, more typically about 2O0g/L to about 350g/L, even -ore typically abcut 250g/L to about 350g/L, and even more typically about 300g/L to about 330g/L, preferably about 330g/L based on the total amount of formulation. Generally, about 12.5mg to about 50mg of oxyciozanide, typically about 16mg to about 37.5mg, more typically about 20mg to about 35mg, even more typicairy'about

25mg to about 35mg, and even more typically about 30mg to about 35mgt preferably about 33mg of salicylanilide per kg bodyweight is applied topically to a mammal in a single dosage.
Generally the amount of macrocyclic lactone used in the formulation ranges from about 2.5g/L to about 25g/L, typically about 4g/L to about 20g/L, more typically about 7.5g/L to about 20g/L and even more typically about 7.5g/L to about 15g/L,. preferably about 15g/L, based on the total amount of formulation. Generally about 0.25mg to about 2.5mg, typically about 0.4 to about 2.Qmg, more typically about 0.75mg to about 2.0mg, even more typically about 0.75mg to about 1.5mg, preferably about 1.5mg of macrocyclic lactone per kg bcdyweight are applied topically to a mammal in a single dosage.
Advantageously, the aqueous micellar formulations according to the invention also comprise a stabilizer. Preferably the stabilizer is selected from anionic surfactants such as linear alkyl sulphates (for example, sodium dodecyl sulphate), linear alkyl benzene sulphonates (such as calcium dodecyl benzene sulphonate) and buffering agents, typically selected from soluble monobasic and/or dibasic phosphates.
Sodium dodecyl sulphate is typically used as a stabiiizer in the formulation in the range of from about 10g/L to about 30g/L, more typically from about lOg/L to about 20g/L, based on the total amount of formulation; phosphates are typically used in the formulation in the range of from about 1g/L to about 10g/L, more typically from about 1g/L to about 5g/L, and more typically from about 1g/L to 2g/L, based on the total amount of formulation.
The aqueous micellar formulations may also include one or more further veterinary excipients, provided these do not destabilise the micellar formulation.
Veterinary acceptable excipients for use in preparing the formulations may include, for example: further solvents such as, for example, water immiscible solvents including glycol ether esters; viscosity modifiers/suspending agents, for example, gelatin, vegetable gums such as xanthan gum, cellulose derivatives (e.g. microcrystalline cellulose, anionic or non-ionic csiluicse ethers, such as carboxymethylcellulose), fumed silica (colloidal silicon dioxide), or polyvinylpyrrolidone polymers, and magnesium aluminium silicates such as VEEGUM® (R.T. Vanderbilt), and mixtures of these.

Examples of suitable veterinary acceptable adjuvants include dyes.

Dyes enable the treated mammals to be distinguished from the untreated. The dyestuff may be dissolved, suspended or dispersed in the carrier. The nature of the colouring agent is unimportant and a wide variety of suitable dyes and pigments will be known to the skilled person. The colouring agent may be solubie or insoluble in water. Generally, however, the dyestuff will be biodegradable so as to fade and not permanently mark the skin or fleece. Some examples of suitable dye agents include: FD&C Brilliant Biue No. 1 (Brilliant Blue FCF, Hexacol Brilliant Blue), and Fast Scarlet Pigment 36
Processes for the preparation of miceJIar formulations of the invention
The micellar formulations according to the invention may be prepared by methods and techniques known to those of skill in the art.
Typically the formulations may be made using a simple process:
Step 1. Charge 80% of the total volume of water-miscible (non flammable) solvent and the surfactant to a manufacturing vessel. Heat to 40°C - 75°C (flammable solvents such "as ethanol and isopropanol, whether added as major water-miscible solvent or as a minor component should be used at ambient temperature).
Step 2. Add the benzimidazole or saiicylaniiide incrementally with continued stirring and heating until dissolved.
Step 3. Add sequentially the water, and optionally stabilizers and dye, stirring until dissolved.
Step 4. Cool to room temperature with continued stirring.
Step 5. Add the macrocyclic lactone incrementally with stirring until dissolved (also, if flammable solvents such as ethanol or isopropanol are to be added as co-solvents, they should be added here).
Step 6. Add the remaining solvent to volume.
Methods of Treatment and/or prevention of diseases or infestations
The formulations according to the invention may be used for the treatment and/or prevention of diseases or infestations by endoparasites in mammals, typically in

livestock such as sheep or cattle, by applying the formulation(s) to the back of the mammal. Important diseases/infestations which may be controlled include liver fluke, nematodes and lice in sheep and cattle and buffalo fly and ticks on
cattle.
It was found that optimal uptake of the active agents into the bloodstream of treated mammals occurred when the formulations were applied to a region starting from the flat part of an animals back - approximately at the location of the thoracic vertebrae - and working towards the rump of the animal, effectively resulting in application of the formulation to the last third of the mammal's back. This mode of application was found to be significantly more effective than application starting at the neck.
Efficiency of delivery of the active agents to the bloodstream of a mammal was also found to be greatest where the surface area to which the formulation is applied was minimised, while avoiding run-off of the formulation, so as to maximise the concentration of active agents per cm2 of animal surface, typically covering an area of about 100cm2 to about 400cm2 for cattle and about 100cm2 for sheep.
Typically the formulation is applied by spray onto the mammal's back, preferably from a constant height relative to the mammal's back.
For cattle, the band of formulation is typically applied starting from the thoracic vertebrae and proceeding towards the rump of the animal. Typically, from about 18mg to about 24mg benzimidazole and from about 0.75mg to about 2.0mg macrocyclic lactone are applied per kilogram animal. More typically, where triclabendazole and ivermectin are the active agents comprised in the formulation from about 18mg to about 24mg, preferably about 24mg triclabendazole and from about 0.75mg to about 2.0mg, preferably about 1.5mg ivermectin are applied per kilogram of animal. Preferably this amount of active agents is applied to the mammal in about 0.05mL to about 0.1 mL per kg animal, and in a band from about 5cm to about 15cm wide. In weaned calves typically weighing from about 100cm to about 180kg per head, good results were obtained by spraying about 10mL to about 18mL formulation onto the backs of the animals, starting from the thoracic vertebrae and working towards the animals' rumps, from a

constant height of about 15cm relative the backs of the animals, resulting in an applied band of formulation about 10cm to about 15cm wide and about 20cm long.
Preferred forms of the present invention will now be described, by way of example only, with reference to the following examples, including comparative data, and which are not to be taken to be limiting to the scope or spirit of the invention in anyway.
Examples
Example 1 - Aqueous micellar formulations, and processes for preparing them
1.1 Formulation A
Component g/L
Triclabendazole 240
Ivermectin 7.5
Polyoxyethylene (20) sorbitan monolaurate (Ecotenc5 T 20) 200
Polyethylene glycol 200 (PEG 200) 30
Water 150
Sodium dodecyl sulphate 20
Brilliant Blue FCF 0.16
Diethylene glycol monobutyl ether to 1L
1.2 Formulation B
Component g/L
Triclabendazole 240
Ivermectin 7.5
Polyoxyethylene (20) sorbitan monoiaurate (Ecoteric® T 20) 200
Polyethylene glycoi 200 (PEG 200) . 30"
Water 250
Sodium dodecyl sulphate 20
Brilliant Blue FCF 0.15
Diethylene glycol monobutyl ether to 1L

1.3 Formulation C
Component g/L
Triclabenclazole 120
Ivermectin 5.0
Poiyalkylene oxide derivative of synthetic alcohol (Teric® BL8) 200
Benzyl alcohol 30
Water 150
Dihydrogen sodium phosphate 7.84
Disodium hydrogen phosphate 0.91.
Brilliant Blue FCF 0.16
Diethylene glycol monobutyl ether to 1L
1.4 Formulation D
Component g/L
Triclabendazole . 120
Ivermectin 5.0
Polyoxyethylene (20) sorbitan monooleate (Ecoteric® T 80) 200
Benzyl alcohol 30
Water 250
Disodium hydrogen phosphate 0.91
Dihydrogen sodium phosphate 7.84
Brilliant Blue FCF 0.16
Propylene glycol monomethyl ether (Glysolv PM®) to 1L
1.5 Formulation E
Component g/L
Oxyclozanide 350
Ivermectin 7.5
Polyoxyethylene (20) sorbitan monooleate (Ecoteric® T 80) 200
Water 150
Sodium dodecyl sulphate 20
Brilliant Blue FCF 0.16
Diethylene glycol monobutyl ether to 1L

1.6 Formulation F
Component g/L
Triclabendazole 240
Ivermectin 10.0
Polyoxyethylene (20) sorbitan monolaurate (Ecoteric T 20) 200
Polyethylene glycol 200 (PEG 200) 30
Water 150
Sodium dodecyl sulphate 20
Brilliant Blue FCF 0 16
Diethylene glycol monobutyl ether to 1L
1.7 Formulation G
Component g/L
Triclabendazole 240 ■
Ivermectin - 15.0
Polyoxyethylene (20) sorbitan monolaurate (Ecoteric T 20} 200
Polyethylene glycol 200 (PEG 200) 30
Water 150
Sodium dodecyl sulphate 20
Brilliant Blue FCF 0.16
Diethylene giycol monobutyl ether to 1L
Other stable aqueous micellar formulations according to the invention are described in Examples 2 and 3.
The formulations were prepared by the following procedure:
Stepi. Charge 80% of the total volume of water-miscibie solvent and the surfactant to a manufacturing vessel. Heat to 40 - 753C with stirring.
Step 2. Add the benzimidazole or salicyianilide incrementally with continued stirring and heating until dissolved.
Step3. Add sequentially the water, and optionally stabilizers and dye, stirring until dissolved.

Step4. Cool to room temperature with continued stirring.
Step 5. Add the macrocyclic lactone incrementally with stirring until dissolved. Step 6. Add the remaining solvent to volume.
Example 2 - Pharmacokinetic studies
Materials and methods
Formulations according to the invention were tested for their efficacy in delivering benzimidazoles and macrocyclic lactones to the bloodstream of mammals (cattle), and compared to the efficacy in delivering these agents to animals' bloodstreams by standard commercially available drench (Fasinex 120®), and an experimental solvent-based triclabendazole/ ivermectin pour-on formulation.
Cattle (typically Hereford or Hereford cross) with either natural or artificially infected burdens of fluke and nematodes were used in pen and field trials. Within a given trial animals were allotted into treatment groups, each having similar mean weights and fluke and nematode burdens. Experimental treatments were applied along the backl-ine using a commercially available backliner gun fitted with a plastic shroud to ensure correct delivery of the formulation according to the protocol.
Blood samples (plasma) were taken by venipuncture of the jugular vein at the designated time intervals. Analysis for triclabendazole and ivermectin residues in the plasma was carried out and reported by commercial contract laboratories .
Ivermectin was extracted from the plasma using acetonitrile and concentrated by svaporation. The sample was cleaned up by solid phase extraction (SPE) :hromatography and the ivermectin determined as the N-methyl imidazole jerivative using reverse phase HPLC with fluorescence detection.
The triclabendazoie was extracted from the plasma using ethyl acetate. Following concentration ancr SPE clean up, the triclabendazoie and its sulphone and >uiphoxide metabolites were analysed by reverse phase HPLC using UV letection.

Results
Initial feasibility studies for development of an efficient fiukicide product were based on the pharmacokinetic profile of triciabendazole only. Although noting that the bioavailability of the active agents is always delayed after application as a pour-on formulation compared to a drench treatment, bleed plasma levels for the experimental formulations were targeted at the maximum triciabendazole plasma levels (Cmax) produced by the currently available fiukicide, Fasirex® 120 (triciabendazole Cmax 16.5^g/mL after 2 days) , when applied at a rate of 12mg/kg bodyweight.

Having reference to Tabie 1, the following results were obtain

ou

In a first feasibility trial (Hereford male weaner cattle, average weight of approximately 200kg, 2 animals per group), a solvent-based formulation (N-methyl pyrrolidone/ Butyl diGlysolv®, Formulation 1), tridabendazole was aopfied at 50mg/kg to achieve similar plasma levels as per the currently available fiukicide, Fasinex® 120 (15.7jig/mL after 7 days). Such a dose rate is not commercially viable.
In a second feasibility trial (Hereford male-and female weaner cattle, average weight of approximately 160kg, 3 animals per group) the triciabendazoie dose rate was reduced to a more commercially acceptable (eve! (12mg/kg). A surfactant (Teric® BL8) was added to Formulation 1 to improve the formulation's hide wettabiiity to produce Formulation 2 (non aqueous micelle), and N-methyi pyrrolidine solvent was removed. Triciabendazoie Crn3X (total metabolite) plasma levels achieved were low (2.0jag/mL).
Addition of 15 % water to Formulation 1 produced Formulation 3 (Formulation C described in Example 1.3 above, an aqueous micelle), and this increased the triciabendazole Cmax achieved to 4.8jag/mL

in a further feasibility trial (Hereford female cattle, average weight of approximately 235kg, 3 animals per group), the water content in the formulation was increased to 25% and Butyl di Giysolv® was replaced with Glysolv PM®. The resulting Formulation 4, provided an increased triciabendazole Cm3x of 8.7jag/mL - almost double that achieved with Formulation 3. The ivermectin Cmax achieved was 1.3ng/mL at 5 days.
A similar formulation, Formulation 5, had a water content of 15 %. Although the Cmax for triciabendazole was almost the same, 8.6^g/mL, the Cmax for ivermectin was 2.6ng/mL at 2 days.
Replacing Teric® BL8 in Formulation 4 with Ecoteric® T20 resulted in - -Formulation 6 (with a water content of 25%) - this formulation achieved substantially the same plasma levels as Fasinex® 120 drench (triciabendazole Cmax of 15.9fig/mL versus 16.5jig/mL) applied at the equivalent dose rate of 12mg/kg. The Cmax achieved for ivermectin was 2.8ng/mL at 5 days.

Formulation 7 again showed increased bioavaiiabiiity of iriclabendazole when Teric® BL8 was replaced with Ecoteric® T30. The Cma* achieved for triclabendazoie was 12.9j.ig/mL and the C m3, achieved for ivermectin was 3.0ng/mLat2days.
Having reference to Table 2, in 3 further feasibility trlai (Hereford female weaner cattle, average weight of approximately 2G0kgf 3 animals per group) reduction of the water content of the formulations to ISGg/L, and reverting to Eccteric^ T20 in place of Ecoteric® T80, increased the efficiency of delivery of ivermectin, the ivermectin plasma Cmax values for the formulations ranging from cng/mL ic 13ng/mL.

From the results provided in Tables 1 and 2, it s aoparent that the pharmacokinetics of the active agents can be altered as desired by manipulating the water content, and the type and content of the surfactant and/or the co-solvent used in micellar formulations according to the invention.

Manipulation of the solvent and co-solvent type has also been found during the course of these experiments to affect the physical stability of the miceilar formulations, use of a combination of Butyl diGlysolv® and PEG 200 providing the best cold storage stability and highest maximum concentration for triclabendazole of the formulations tested, thereby providing a more rugged product suitable for application tc animals in the cooler months of late autumn or early spring - although there is no published data, it has been reported thai greater amounts of active components need to be applied to animals in colder months to get the required efficacy, and these months are typically the most important in liver fluke control.
Example 3 - Dosing studies
Example 3.1 - Concentration affect (constant volume)
Having reference to Table 2, it can be seen that altering the concentration of triclabendazole and/or ivermectin in the aqueous miceliar formulations of the invention provides a corresponding change in AUC, when applied to the animal in the same volume of formulation (1mL applied/ 10kg animal).
Example 3.2 - Concentration effect (constant dose)
Having reference to Table 3, in a critical slaughter efficacy trial of formulations according to the invention (methods as per Example 2; mixed sex Hereford weaner cattle, average weight of approximately 200kg, 5 animals per group), an aqueous miceilar formulation according to the invention comprising triclabendazole at 240g/l, but varying ivermectin concentration was applied at a constant ivermectin dosage rate (0.5mg/kg)f but varying triciabendazoie dosage rate(12to36mg/kg).
The results show that application of a more concentrated ivermectin dose in a smaller volume (same final ivermectin dose rate), resulted in improved pharmacokinetic results, including greater Cmax and/or greater bicavailability
(AUC) of thft i

in another trial (also carried out as described in Example 2), a formulation according to the invention having 130g/L triciabendazole anc 7.5g/L ivermectin, and a formulation having 240g/L triclabendazoie and IC5/L ivermectin, were applied to animals over different area sizes on the backs of the animals (from the middle of the back towards the rump)r while maintaining the same dose rate for the active constituents. The results, shewn in Table 4, show that appiicaticn of the ivermectin and triciabendazole in a higher concentration "crmuiatlon applied over a smaller area makes the active agents more bioavailabie.

Example 4 - Stability studies
Samples of formulation A, the composition and preparation of which is described in Example 1, which contains sodium dodecyl sulphate, were stored at 4, 30 and 40°C in 250 mL high density polyethylene bottles sealed with screw caps, sampled at 1, 2, 3, 6 and 12 months, and tested for ivermectin and triciabendazole content. Triclabendazole and ivermectin content of the formulations was determined using validated stability indicating methods based on reversed phase HPLC with UV detection. The results, provided in Table 5, demonstrate the chemical stability of the formulation at accelerated storage conditions - effectively no degradation of the active components occurred even after 6 months storage at 40°C. After 12 months storage at 30°C there was stii! no measured degradation of the triciabendazoie and ivermectin components. After 12 month-s at 40°C there was less than 5% breakdown of the ivermectin component.

Samples of formulation G, the ccnccsiticn and preparation of whicr. is described in Example 1, which contains sccium dcdecyi sulphate, were stored at 4. 30 and 40°C in 250 mL high density polyethylene bottles sealed with screw caps, sampled at 1, 2 and 3 months, and rested for ivermectin and trlciabendazole content. Triclabendazole and ivermsctin content of ir.e formulations was determined using validated stability indicating methods based on reversed phase HPLC with UV detection. The results, provided in Table 6, demonstrate the chemicaf stability of the formulation at accelerated storage conditions -effectively no degradation of the active components occurred even after 2 months storage at 30 or40°C.

In another stability trial a number of substances were tested 'or their potential as a stabilizer for the formulations, ivermectin being unstable in iradequately stabilised formulations. The substances were each tested ai a concentration of 10.0 g/L, except phosphate buffers, in a formulation otrenvise ^aving the following composition (per Litre):
Triclabendazole 120g
Ivermectin 5.Cg
Teric BL 3® 200g

Benzyl alcohol 30g
Water 150g
Brilliant Blue FCF 0.16g
Butyl Di Glysolv® approximately 485 mL (to volume)
The samples were stored at 50°C in 250 mL nigh density polyethylene bottles sealed with screw caps, and sampled at 3 months, and tested for ivermectin and triclabendazole content. Triclabendazole and sverrnectin content of the formulations was determined using validated stability indicating methods based en reversed phase HPLC with UV detection. The data, provided :n ^able 7, illustrate the difficulty of stabilising the ivermeciin component of the formulation.
From the stability data it was concluded that inclusion of anionic surfactants such as the linear alkyl sulphate sodium dcdecyl sulphate, or buffering agents such as one or more monobasic/ dibasic phosphates, or mixtures thereof, in the formulations of the invention significantly improve the stability of the ivermectin component.

Example 5 - Efficacy studies
Materials and Methods
Cattle (typically Hereford or Hereford cross breed) with either natural or artificially infected burdens of fluke and nematodes were used in pen and field trials. They were allotted into treatment groups, each having similar mean weights and fiuke and nematode burdens. Experimental treatments were applied aiong the backline from the middle of the back towards the rump, using a commercially available backliner gun fitted with a plastic shroud to ensure correct delivery of the formulation according to the protocci.
Efficacy was measured by either decrease in faecal egg counts over time or total parasite counts from gastrointestinal tracts and livers recovered after slaughter. The reported data are based on group arithmetic and/or grcup'geornetric means.
Efficacy based on faecal worm egg counts were calculated as follows: % Efficacy = 100 [ 1 - (T2 Ci/ T^ C2)]
where T, C, 1 and 2 refer to treated, control, pre-treatrnent and post treatment mean worm egg counts respectively.
All other Efficacy data were calculated using the formula: %Efficacy= 100(C-T/C)
where T and C refer to treated and control mean total worm counts respectively.
For critical slaughter nematode efficacy studies, the animals were slaughtered at 14 or 21 days post treatment.
For critical slaughter efficacy studies against ali stages of the liver fluke (artificially infested), the animals were slaughtered 100 days after treatment.
Results
Example 5.1
A critical slaughter pen efficacy thai (naturally acquired fluKe and nematodes) involved mixed sex Hereford and Hereford/Angus cross weared calves selected from 2 large commercial herds. The animals were randomly allocated to groups of 5 animals such that each group had a similar mean and range of Fasciola hepatica egg counts and body weights. Prior to treatment, animals were moved

to a research feedlot to avoid further infection. At treatment the animals were weighed and treated with formulations of the triclabendazole + ivermectin pour on administered at different dose volumes and active concentrations. One group of 5 animals remained as untreated negative control.
All animals were slaughtered 19 to 21 days post treatment, gastrointestinal tracts and livers recovered, and total worm and fluke numbers determined.
Treatment formulations involving different concentrations of-active components and/or different excipients were tested, these formulations being as follows:
Group 1 q or mUL Dosage rate (mq/kg)
Triclabendazole 240g 12
Ivermectin 10.0g 0.5
Ecoteric T20® 200g
PEG 200 30g
Water - 150g
Triethanolamine 0.74g
Brilliant Blue FCF 0.16g
Butyl diGlysolv® 491 mL
Group 2 q or mUL Dosage rate (mg/kq)
Triclabendazole 240g 24
Ivermectin 5.0g 0.5
Ecoteric T20® 20Og
PEG 200 30g
Water 150g
Triethanolamine 1.27g
Brilliant Blue FCF 0.16g
Butyl diGlysolv® 494mL
Group 3
Triclabendazole 240g 36
Ivermectin 3.33g 0.5
Ecoteric T20® 200g
PEG 200 30g
Water 150g
Triethanolamine 1.12g
Brilliant Blue FCF 0.16g
Butyl diGlysolv® 498mL
Group 4
Triclabendazole 240g 24
Ivermectin 5.0g 0.5
Ecoteric T20® 180g
PEG 200 30g
Water 150g
Brilliant Blue FCF 0.16g
Sodium dodecyl sulphate 20g
Butyl diGlysolv® 480mL

Group 5 q or mUL Dosage rate (mq/ko)
Triciabendazole 240g 24
Ivermectin 5.0g 0.5
Ecoteric T20® 200g
PEG 200 30g
Water 150g
Brilliant Blue FCF 0.16g
Sodium dodecyl sulphate 20g
Butyl diGlysolv® 480mL
Group 6
Triciabendazole 240g 24
Ivermectin 5.0g 0.5
Ecoteric T20® 200g
PEG 200 30g
Water 150g
Brilliant Blue FCF 0.16g
Sodium dodecyl sulphate 20g
Butyl diGiysolv® 316ml
Ethylene glyco'diacetate i55mL
The results, provided in Table 8, show that effective control of flukes and nematodes is achievable using a practical volume of an aqueous miceilar pour-on formulation of the present invention.
The product was 100 % effective against adult Fasciola hepatica at dose rates of 12, 24 and 36 mg/kg triciabendazole and effective against nematodes at a dose rate of 0.5 mg/kg ivermectin. In this trial, an effective treatment of animals for endoparasites was achieved using 1mL/ 20kg of a formulation including 240g/L triciabendazole and 10.0g/L ivermectin (12mg/kg triciabendazole and 0.5 mg/kg ivermectin).

Example 5.2
Two critical slaughter studies were designed to compare the efficacy of a formulation according to the invention (see below) against immature and adult stages of the liver fluke Fasciola hepatica, and naturally acquired roundworm infections in cattle. The efficacy of the triclabendazole +" ivermectin pour-on against immature and mature stages of Fasciola hepatica based on arithmetic

mean was 70.5% and 99.2% respectively. Control of gastrointestinal strongyles by the test formulation (Group 5, Example 5.1, Table 8) as assessed using total worm counts at slaughter was 86% to 99.9% (arithmetic mean) for nematodes found in the abomasum, small and large intestines.
Test formulation -described in Example 1.1, Formulation A
Component g or mL/L Dose Rate (mg/kg)
Triclabendazole 240g 24.0
Ivermectin 7.5 a 0.75
Ecoteric T20® 200g
PEG 200 30g
Water 150g
Brilliant Blue FCF 0.16g
Sodium dodecyl sulphate 20g
Butyl diGlysoiv® approximately 475 mL (to volume)
Example 5.3
Three field trials (faecal egg count reduction tests) were designed to determine the efficacy of the formulation described in Example 5.2 under field conditions. Sixty cattle were split into groups of 15, one of the groups remaining as an untreated control. Good efficacy of the formulation against Fasciola hepatica as assessed by a reduction in faecal egg counts as compared to the untreated controls of >90% (AM) was reported in all trials 14 days post treatment.
Example 5.4
A field trial was designed to determine the efficacy of the following formulation against a mixed natural infection of adult and immature liver flukes and adult and immature nematode species.
Component g /L Dose Rate (mg/kg)
Triclabendazole 240g 24.0
Ivermectin 7.5 g 0.75
Ecoteric T20® 200g
PEG 200 30g

Water 150g
Brilliant Blue FCF 0.16g
Sodium doclecyl sulphate 20g
Butyl diGlysolv® approximately 450 mL (to volume)
Thirty (30) Angus cross and Limousin cross weaners, between 5 and 6 months of age, and weighing 112-242 kg, were selected from a larger commercial herd running at Armidale, New South Wales, Australia, on the basis of pre trial individual strongyle egg counts. The cattle grazed in open paddocks on a mixture of native and improved pasture with supplementary feed (buckwheat) provided on a daily basis. Over the treatment period at the Armidaie Saleyards cattle had ad-lib access to Lucerne hay. The cattle had not been exposed to any anthelmintic treatments for a period of three (3) months prior to the trial start date.
Prior to treatment cattle were ranked from highest to lowest on individual pre trial liver strongyle faecal egg counts (Day -3), split into females and castrated males, blocked and randomly allocated to two (2) treatment groups such that the groups had a similar mean and range of strongyle faecal egg counts within the group. On day zero (0), all trial cattle were weighed and vaccinated with UltraVac 7 in 1 Vaccine (CSL Limited). The animals of Group 1 were left untreated, serving as negative controls. Group 2 was treated with the triclabendazole (240g/L) + ivermectin (7.5g/L) pour on formulation applied topically from the middle of the back to the base of the tail at a dose volume of 1mL/10kg. A prototype applicator which ensured the formulation was applied as a wide band was used for treatment.
Faecal samples were collected from all trial cattle on day zero (0) and on days seven (7) fourteen (14) twenty one (21) and twenty eight (28) of the trial. Strongyle and liver fluke faecal egg counts and group bulk coprocultures for larval differentiation were performed on samples collected. Raw strongyle and fluke faecal egg counts were collated by treatment group and arithmetic means calculated. Geometric means were also calculated using transformed individual egg counts. Treatment efficacy, based on both arithmetic and geometric group means were calculated as follows:
% Efficacy = (control group mean - treatment group mean)/control group mean x 100

Pre treatment Fasciola and strongyle faecal sgg counts were high, with a mean Strongyle faecal egg count of 802.7 e.p.g. (range 160-6120) and a mean Fasciola faecal egg count of 46 e.p.g. (range 0-1525) pre trial. Five genera of helminths were identified from group bulk coprocuitures including; Haemonchus spp., Trichostrongylus spp., Ostertagia spp,} Cooperia spp and Oesophagostomum spp.. Coooena sop made UD on average 70% of the bulk coproculture for the untreated controls from cay 0 to day 28. Group arithmetic and geometric mean Fasciola faecal egg counts over the duration of the trial -are presented in Table 9. Good control {>90% efficacy arithmetic mean, >97% efficacy geometric mean) of Fascioia hepaiica was achieved with the triclabendazole + ivermectin pour on, 7, 1^, 21 and 23 days pest treatment. Treatment efficacies based on arithmetic and geometric mean fluke faecai egg counts are presented in Table 10.

Group arithmetic and geometric mean strongyie faecai egg counts over the duration of the trial are presented in Table 11. Efficacy of the triciabendazole + ivermectin pour on against strongyles was greater than 93% (geometric means) 7 and 28 days post treatment, and 89-8% and 83.5% 14 and 21 days post treatment. Efficacy based on arithmetic and geometric faecal egg counts are presented in Table 12.

Example 5.5
A further field trial was designed to determine the efficacy ..of the formulation described in Example 5 4 against a mixed natural infecticn of aduit and immature liver flukes and adult and immature nematode species.
Thirty (30) Angus and Angus cross heifers, between 12 and 14 months of age, and weighing 126-284 kg, were selected from a larger commercial herd running at Walcha, New South Wales, Australia, on the basis of pre trial individual strongyle egg counts. The cattle grazed in open paddocks on a mixture of native and improved pasture with ad-lib access to water. The cattle had not been exposed to any anthelmintic treatments for a period of three (3) months prior to the trial start date.
Prior to treatment cattle were ranked from highest to lowest on individual pre trial liver strongyle faecai egg counts (Day -1), blocked and randomly allocated to .two (2) treatment groups such that the groups had a simiiar mean and range of strongyle faecal egg counts within the group. On day zero (0), all trial cattle were weighed. The animals of Group 1 were left untreated, serving as negative controls. Group 2 was treated with the triclabendazole (240g/L) + ivermectin (7.5g/L) pour on formulation applied topically from the middle of the back-te the

base of the tail at a dose volume of 1mL/10kg. A prototype applicator which ensured the formulation was applied as a wide band was used for treatment.
Faecal samples were collected from all trial cattle on day zero (0) and on days seven (7) fourteen (14) twenty one (21) and twenty nine (29) of the trial. Strongyle faecal egg counts and group bulk coprocuitures for larval differentiation were performed on samples collected. Raw strongyle egg counts were collated by treatment group and arithmetic means calculated. Geometric means were also calculated using transformed individual egg counts. Treatment efficacy, based on both arithmetic and geometric group means were calculated as fellows:
% Efficacy = (control group mean - treatment group mean)/control group mean x 100
Pre treatment strongyie faecal egg counts were high, with a mean Strongyle faecal egg count of 288 e.p.g. (range 40-1320). Four genera of helminths were identified from group bulk coprocuitures at day zero (0) including: Haemonchus spp., Ostertagia spp., Cooperia spp and Oesophagostomurn spp.: Cooperia spp made up on average 70-80% of the bulk coprocuiture for the untreated controls from day 0 to day 29. Group arithmetic and geometric mean strongyle faecal egg counts over the duration of the trial are presented in Table 13. Efficacy of the triclabendazole + ivermectin pour on against strongyies reached a maximum 84% reduction in egg counts (arithmetic means) 7 days post treatment, and 78%, 59% and 63% 14, 21 and 29 days post treatment. Treatment efficacies based on arithmetic and geometric strongyle egg counts are presented in Table 14.

Example 5,6
A dose evaluation critical slaughter study was designed to compare the pharmacokinetics and efficacy of the developmental topical triclabendazoie + ivermectin formulation described in Example 5.4 (240g/L triclabendazoie and 7.5 g/L ivermectin), and the developmental topicai triciabendazole + ivermectin formulations of formulae F (240 g/L triclabendazoie and 10 g/L ivermectin) and G (240 g/L triciabendazole and 15 g/L ivermectin) described in Examples 1.6 and , 1.7 respectively against a mixed natural infection of gastrointestinal strcngyies, so as to determine the optimum concentration of ivermectin in the formulation for effective control of Cooperia spp as well as the other nematodes.
Fifty (50) Hereford and Angus cross steers, aged between five to six (5-6) months and weighing between 102-164kg at treatment, were selected from a larger mob at Casino on the North Coast of NSW; Australia on the basis of pre trial individual strongyle faecal egg counts. The cattle were relocated to "Kirby", Armidale NSW, Australia twenty days prior to treatment and grazed In open paddocks on a mixture of native and improved pastures. Trial cattle were fed Lucerne hay while they were held in the Armidale Saleyards (day 0 through to day 2). The cattle had not been exposed to triciabendazole or ivermectin for a period of three (3) months prior to the trial start date and had no known resistance by gastrointestinal strongyles to macrocyclic lactcnes.
Five (5} days prior to treatment faecal samples were collected from each animal for individual faecal egg counts and bulk coproculture. Triplicate blood samples were collected for triciabendazole and ivermectin plasma analysis: One (1) day prior to treatment Twenty five (25) trial cattle were re-located to the Armidale Saleyards, ranked from highest to lowest according to individual egg counts (day -5), sequentially blocked and allocated at random to five (5; groups of five (5) animals, such that each group had a similar mean and ranee of strnnnvi** fa^ooi

egg counts. The animals of Group 1 were left untreated, serving as negative controls. Group 2 was treated with the 240g/L trictabendazole + 7.5g/L ivermectin pour on formulation. Group 3 was treated with the 240g/L triclabendazole + 10.0g/L ivermectin pour on formulation. Group 4 was treated with the 240g/L triclabendazole + 15.0g/L ivermectin pcur on formulation. Ail formulations were applied topically from the middle of the back to the base of the tail at a dose volume of 1mL/10kg (according lo a dose break table). A prototype applicator which ensured the formulation was applied as a wide band was used for treatment. Two (2) day after treatment all cattle were re-located from the Armidale Saleyards to the Kirby feedlct for the remainder of the trial.
Faecal samples were collected frcm each individual animai in all groups five {5} days prior to treatment then nine (9) for Individual faecal egg counts and coprocultures pre and post treatment. Ail trial cattle were sacrificed 13, 14 and 15 days post treatment. Faecal samples, abomassa, small intestine and large intestine were collected from each anima! for faecal egg counts, group coprocultures and total worm counts (adult and immature). Treatment efficacy was assessed by comparison of group arithmetic and geometric mean total worm counts (as described in Examples 5.4 and 5.5) by nematode species and strongyle faecal egg counts following sacrifice and organ recovery.
Pre treatment egg counts were generally high ranging frcm 480-1480 eggs per gram (e.p.g.) of faeces.
At 13 - 15 days post treatment, animals treated with the pour-on formulations produced a reduction in egg counts when compared to the untreated controls of between 73% (240 g/L triclabendazoie plus 7.5 g/L ivermectin) to 98% (240 g/L triclabendazole plus 15.0 g/L ivermectin) (arithmetic means) and between 94 % and > 99 % respectively (geometric means). (Table 15).

At necropsy, seven (7) genera of heirninths were recovered from the gastrointestinal tract of the control cattle approximately 80% of which consisted of adult, immature and L4 stages of Cooperia spp. Other gastrointestinal nematodes identified include Trichuris spp, Nematodirus spp. Oesophagosornum spp. Trichostrongylus spp, Haemonchus spp and Ostertagia spp which each made up approximately 5% or less of the total count.
Total worm count data indicated that the small intestinal worms, Coopeha spp. and adult Nematodirus spp,t were the most difficult species to remove following treatment. Efficacy increased with increasing concentration of ivermectin in the formulation.
The 240 g/L triclabendazole plus 15.0 g/L ivermectin formulation efficacy against adult and immature stages of small intestinal nematodes (Trichostrongylus sppt Cooperia spp) was greater than 90% (arithmetic and geometric means) and greater than 99% (geometric means) with the exception of adult Nematodirus [49.1% (arithmetic means) and 93 % (geometric means)].
Greater than 95% efficacy (geometric and arithmetic) was achieved against adult and immature stages of abomasal nematodes (Haemonchus 3pp, Ostertagia ostertagia, Trichostrongylus axef; and large intestinal nematodes (Oesphagostomum sppr Trichuris spp).
Greater than 95% efficacy (arithmetic and geometric means/ was achieved by the 240g/L tridabendazoie plus 7.5g/L ivermectin and the 240g/L triclacendazoie

plus 10g/L ivermectin formulations against abomasal nematodes (with the exception of fourth stage Ostertagia larvae in cattle treated with the 240g/L triclabendazole plus 10g/L ivermectin formulation ). Efficacy against small intestinal nematodes increased from 57.7% to greater than 99.9% with increased concentration of ivermectin.

Triplicate blood samples were also collected five (5) days prior to treatment then 1, 3, 5 and 7 days post treatment from animals in groups 2, 3, 4 and 5 for triclabendazole and ivermectin analysis. Plasma ivermectin C^x and AUC values increased relative to the concentration in the formulation - Table 17.

Summary:
For a given dose volume (1mL per 10 kg bcdyweight), increasing the concentration of ivermectin in the formulation increased the plasma concentration and efficacy. Nematode efficacy of the 240 g/L triclabendazole plus 15.0 g/L ivermectin was higher and more consistent than the corresponding formulations containing 7.5 and 10,0 g/L ivermectin, especially against the hard to control small intestinal worms, Cooperia spp and Nematodirus spp.
Industrial Appticability
The formulations of the invention can be readily used to treat, control or prevent disease caused by, and/or infestations of, endo-parasites such as liver fluke and nematodes as well as ecto-parasites, particularly in treating, controlling and/or preventing liver fluke and nematode infestations in sheep or cattle, particularly cattle.
It will be appreciated that, although specific embodiments of the invention have been described herein for the purpose of illustration, various modifications may be made without deviating from the spirit and scope cf the invention as defined in the following claims.

What is claimed is:
1. An aqueous micellar formulation comprising a first active agent,
selected from water insoluble benzimidazoles, salicylanilides and active
derivatives or salts thereof, in combination with a second active agent, selected
from macrocyclic Iactones or active derivatives or salts thereof, said formulation
being for topical application to animals for the control of internal parasites and
also comprising, per litre of formulation:
from about 100g to about 400g veterinary-acceptable surfactant(s); from about 200g to about 750g veterinary-acceptable water-miscibte solvent(s); and from about 50g to about 350g of water.
2. A formulation according to Claim 1, wherein said surfactant is selected
from polyoxyethylene sorbitan fatty acid esters or combinations thereof.
3. A formulation according to Claim 2, wherein said surfactant is
polyoxyethylene (20) sorbitan monolaurate.
4. A formulation according to any one of Claim 1, wherein said water-
miscible solvent is selected from ethanol, isopropanol, benzyl alcohol, glycoi
ethers, liquid polyoxyethylene glycols, or a mixture of at least two of these
solvents.
5. A formulation according to Claim 4, wherein one or more of the glycoi
ethers are selected from alkylene ordialkylene glycoi monoalkyl ethers.
6. A formulation according to Claim 5, wherein said one or more of glycoi
ethers are selected from propylene glycoi monomethyl ether, diethylene glycoi
monoethyl ether, and diethylene glycoi monobutyl ether.
7. A formulation according to Claim 4, comprising a glycoi ether and a
liquid polyethylene glycoi as water-miscible solvents.
8. A formulation according to Claim 7, wherein the polyethylene glycoi is
PEG 200.
9. A formulation according to Claim 1, further comprising from about 5g
to about 50g per litre of formulation of a stabilizer selected from linear anionic
surfactants, buffering agents and mixtures thereof.
10. A formulation according to Claim 9, wherein said stabilizer is selected
from linear alkyl sulphates, linear alkyl benzene sulphonates, and phosphates, or
mixtures thereof.

11. A formulation according to Claim 10, wherein said stabilizer is sodium
dodecyl sulphate.
12. A formulation, according to Claim 1t comprising about 100g tc about
300g surfactant per litre of formulation.
13. A formulation according to Claim 1, comprising from about 3Q0g tc
about 650g water-miscible solvent(s) per litre of formuiation,
14. A formulation accordina to claim 1, wherein said formuiation comorises
from about 10g to about 100g per litre of formulation of a liquid polyeihyiene
glycoi as a water-miscible solvent.
15. A formulation according to Claim 13, comprising about 450g tc about
550g glycoi ether(s) selected from alkylene or dialkylene giycoi monoalkyi ethers,
and about 20g to about 50g of a liquid polyethylene giycoi as the one cr more
water-miscible solvents per litre of formulation.
16. A formulation according to Claim 1, comprising about 150g water per
litre of formulation.
17. A formulation according to Claim 1, comprising from about 120g to
about 300g benzimidazole, or a derivative thereof, per litre of formulation.
18. A formulation according to Claim 16 or Claim 17, wherein said first
active agent is triclabendazole.
19. A formulation according to Claims 1, comprising from about 7.5g to
about 20g macrocyclic lactone per litre of formulation.
20. A formulation according to Claim 19, comprising about 15g
macrocyclic lactone per litre formulation.
21. A formulation according to Claim 19 or Claim 20, wherein said
macrocyclic lactone is ivermectin.
22. A formulation according to Claim 1, comprising, per litre of
formuiation:
about 180g to about 240g benzimidazole;
about 7.5g to about 20g macrocyciic lactone or an active derivative or
salt thereof;
about 150g to about 250g polyoxyethylene (20) sorbitan mortoiaurate;
about 450g to about 550g diethylene giyco! monobutyi ether;
about 20g to about 50g PEG 200;
about 10g to about 30g sodium dodecyl sulphate; and
about 100g to about 200g of water.

23. The formulation of Claim 22 which comprises about 240g
triclabendazole and about 15g ivermectin per litre.
24. A method of treating or preventing a diseased or parasite-infested
state in a mammal, comprising topically administering to said mammal a micellar
formulation according to Claim 1 or Claim 22, wherein said disease or parasite-
infested state comprises a liver fluke infection or infestation, a nematode
infection or infestation, or both a liver fluke and a nematode infection or
infestation in a mammal.
25. A method according to Claim 24, wherein said mammal is selected
from cattle, sheep, goats, pigs and horses.
26. A method according to Claims 24, wherein said topical application
comprises application of the formulation in a band along the lower portion of the
back of the mammal.
27. A method according to Claim 26, wherein the formulation is applied to
the mammal over as small a region as possible, while avoiding run-off of the •
formulation so as to maximise the concentration of active agents per cm2 of
animal surface.
28. A method according to Claim 26, wherein the band of formulation is
applied starting from the thoracic vertebrae and proceeding towards the rump of
the animal, and from about 18mg to about 24mg triclabendazole and from about
0.75mg to about 2mg ivermectin are applied per kilogram animal.
29. The method of Claim 28, wherein about 24mg tricfabendazole and
about 15mg ivermectin are applied per kilogram animal.

Documents:

865-CHENP-2005 CLAIMS GRANTED.pdf

865-CHENP-2005 POWER OF ATTORNEY.pdf

865-chenp-2005-abstract.pdf

865-chenp-2005-claims.pdf

865-chenp-2005-correspondnece-others.pdf

865-chenp-2005-correspondnece-po.pdf

865-chenp-2005-description(complete).pdf

865-chenp-2005-form 1.pdf

865-chenp-2005-form 18.pdf

865-chenp-2005-form 3.pdf

865-chenp-2005-form 5.pdf

865-chenp-2005-pct.pdf

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Patent Number

219662

Indian Patent Application Number

865/CHENP/2005

PG Journal Number

27/2008

Publication Date

04-Jul-2008

Grant Date

13-May-2008

Date of Filing

09-May-2005

Name of Patentee

SCHERING-PLOUGH LTD

Applicant Address

Inventors:

#	Inventor's Name	Inventor's Address
1	SHEPHERD, STANLEY

PCT International Classification Number

A61K 31/365

PCT International Application Number

PCT/AU03/01490

PCT International Filing date

2003-11-11

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	2002952597	2002-11-11	Australia